feat(run): show externally started Claude sessions in the active-runs list

The Workspace active-runs list only knew about runs this dashboard spawned,
so two `claude` sessions started by hand in terminal tabs showed up nowhere —
the list read "no active runs" while two agents were working.

Poll GET /api/sessions?status=active alongside the run list and merge those
sessions in as live rows, deduped against dashboard runs by session_id and
filtered to local sources with a cwd (a remote-source or cwd-less session
cannot be resumed on this machine).

External rows get no Attach action: the dashboard owns no tmux session for
them, so there is no PTY to bridge. They offer Resume, which reuses the
existing ensure-lane + start-with-resumeSessionId path to spawn a new
tmux-backed `claude --resume` in that folder — a second process on the same
transcript, not a view of the original terminal.

client/src/components/lanes/LaneStripCard.tsx

@@ -1,9 +1,9 @@
 /**
- * @file The compact lane tile used in the Workspace carousel. It carries only
- * what you need to pick a lane — which lane, is it alive, what stage, how far —
- * because the full card, its controls and its working-copy facts live in the
- * detail panel below. Keeping the tile small is what lets a dozen lanes stay
- * scannable in one horizontal row.
+ * @file The compact lane tile used in the Workspace's vertical lane list. It
+ * carries only what you need to pick a lane — which lane, is it alive, what
+ * stage, how far — because the full card, its controls and its working-copy
+ * facts live in the detail panel beside it. Keeping the tile small and full
+ * width is what lets many lanes stay scannable in one scrolling column.
  * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
  */
 
@@ -42,7 +42,7 @@ export default function LaneStripCard({
       aria-pressed={selected}
       onClick={onSelect}
       title={lane.cwd}
-      className={`w-56 shrink-0 snap-start rounded-lg border p-3 text-left shadow-sm transition-colors ${
+      className={`w-full shrink-0 rounded-lg border p-3 text-left shadow-sm transition-colors ${
         selected
           ? "border-accent bg-accent/10"
           : "border-border bg-surface-2 hover:border-border-light hover:bg-surface-3"

client/src/components/run/LaneConsolePane.tsx

@@ -0,0 +1,408 @@
+/**
+ * @file LaneConsolePane.tsx
+ * @description One lane's run console: the RunSetup ↔ TerminalView switcher,
+ * moved out of Workspace.tsx so the Workspace page can render 1, 2, or 4 of
+ * these side by side (split terminal view). Owns its own prompt/cwd/model/
+ * permissionMode/effort/resumeSession/handle/busy/runHistory state — nothing
+ * is shared between panes. `lanes`, `binaryStatus`, `cwdSuggestions`,
+ * `activeRuns`, and `externalSessions` are supplied as props because they are global, not
+ * lane-specific, and fetching them per pane would mean N redundant identical
+ * requests for an N-pane layout.
+ * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
+ */
+
+import { useCallback, useEffect, useState } from "react";
+import { useTranslation } from "react-i18next";
+import { Play, AlertCircle } from "lucide-react";
+import { api } from "../../lib/api";
+import type {
+  CwdSuggestion,
+  DashboardRunHistoryItem,
+  EffortLevel,
+  PermissionMode,
+  RunHandle,
+  RunListResponse,
+  RunStartArgs,
+} from "../../lib/api";
+import type { Session, Lane } from "../../lib/types";
+import { TerminalView } from "./TerminalView";
+import { RunSetup } from "./RunSetup";
+import { ActiveRunsSwitcher } from "./RunHistory";
+
+export interface LaneConsolePaneProps {
+  lanes: Lane[];
+  laneId: number | null;
+  showLaneSelector: boolean;
+  onLaneIdChange: (id: number) => void;
+  onLaneCreated: (lane: Lane) => void;
+  binaryStatus: { found: boolean; path: string | null } | null;
+  cwdSuggestions: CwdSuggestion[];
+  activeRuns: RunListResponse | null;
+  /** Active Claude Code sessions started outside the dashboard, listed in the
+   *  active-runs switcher alongside dashboard runs. */
+  externalSessions?: Session[];
+  wsConnected: boolean;
+  defaultCwd?: string;
+  onHasActiveRunChange?: (active: boolean) => void;
+}
+
+export function LaneConsolePane({
+  lanes,
+  laneId,
+  showLaneSelector,
+  onLaneIdChange,
+  onLaneCreated,
+  binaryStatus,
+  cwdSuggestions,
+  activeRuns,
+  externalSessions,
+  wsConnected,
+  defaultCwd,
+  onHasActiveRunChange,
+}: LaneConsolePaneProps) {
+  const { t } = useTranslation("run");
+  const { t: tLanes } = useTranslation("lanes");
+  const { t: tCommon } = useTranslation("common");
+
+  const [prompt, setPrompt] = useState("");
+  const [model, setModel] = useState("");
+  const [permissionMode, setPermissionMode] = useState<PermissionMode>("acceptEdits");
+  const [effort, setEffort] = useState<EffortLevel>("");
+  const [cwd, setCwd] = useState(() => lanes.find((l) => l.id === laneId)?.cwd ?? defaultCwd ?? "");
+  const [resumeSession, setResumeSession] = useState<Session | null>(null);
+  const [handle, setHandle] = useState<RunHandle | null>(null);
+  const [busy, setBusy] = useState<"start" | "kill" | "attach" | null>(null);
+  const [error, setError] = useState<string | null>(null);
+  const [runHistory, setRunHistory] = useState<DashboardRunHistoryItem[]>([]);
+
+  const currentLane = laneId !== null ? lanes.find((l) => l.id === laneId) : null;
+
+  useEffect(() => {
+    onHasActiveRunChange?.(handle !== null);
+  }, [handle, onHasActiveRunChange]);
+
+  useEffect(() => {
+    if (!currentLane && defaultCwd && cwd === "") {
+      setCwd(defaultCwd);
+    }
+  }, [defaultCwd, currentLane, cwd]);
+
+  const refreshList = useCallback(() => {
+    if (laneId !== null) {
+      api.run
+        .history(50, { laneId })
+        .then((r) => setRunHistory(r.items))
+        .catch(() => undefined);
+    } else {
+      api.run
+        .history(50)
+        .then((r) => setRunHistory(r.items))
+        .catch(() => undefined);
+    }
+  }, [laneId]);
+
+  const attachToRun = useCallback(
+    async (id: string) => {
+      if (busy) return;
+      setBusy("attach");
+      setError(null);
+      try {
+        const fetched = await api.run.get(id);
+        setHandle(fetched);
+      } catch (err: unknown) {
+        const m = err instanceof Error ? err.message : "unknown";
+        setError(t("errors.attachFailed", { message: m }));
+      } finally {
+        setBusy(null);
+      }
+    },
+    [busy, t]
+  );
+
+  const onStartFromSetup = useCallback(
+    async (args: RunStartArgs) => {
+      if (busy) return;
+      setBusy("start");
+      setError(null);
+      try {
+        const effectiveCwd = args.cwd || undefined;
+
+        if (!effectiveCwd) {
+          throw new Error(t("errors.cwdRequired"));
+        }
+
+        // Resolve the lane from the cwd the user actually typed, not from
+        // args.laneId — RunSetup always supplies this pane's laneId (a
+        // required prop), which would otherwise silently start a run in the
+        // wrong lane whenever the user types a cwd different from the one
+        // this pane currently shows.
+        const ownedLane = lanes.find((l) => l.cwd === effectiveCwd);
+        let targetLaneId: number;
+        if (ownedLane) {
+          targetLaneId = ownedLane.id;
+          if (ownedLane.id !== laneId) onLaneIdChange(ownedLane.id);
+        } else {
+          try {
+            const ensureResult = await api.lanes.ensure({ cwd: effectiveCwd });
+            targetLaneId = ensureResult.lane.id;
+            onLaneIdChange(ensureResult.lane.id);
+            onLaneCreated(ensureResult.lane);
+          } catch (err) {
+            throw new Error(
+              t("errors.laneCreateFailed", {
+                message: err instanceof Error ? err.message : "unknown",
+              })
+            );
+          }
+        }
+
+        let laneStartResult;
+        try {
+          laneStartResult = await api.lanes.action(targetLaneId, "start", {
+            prompt: args.initialPrompt || "",
+            model: args.model || undefined,
+            permissionMode: args.permissionMode,
+            resumeSessionId: args.resumeSessionId,
+            effort: args.effort || undefined,
+          });
+        } catch (laneErr: unknown) {
+          const msg = laneErr instanceof Error ? laneErr.message : String(laneErr);
+          if (msg.includes("409") || msg.includes("ERUNLIVE")) {
+            const fresh = await api.lanes.list().catch(() => null);
+            const updatedLane = fresh?.lanes.find((l) => l.id === targetLaneId);
+            if (updatedLane?.run_id) {
+              await attachToRun(updatedLane.run_id);
+              return;
+            }
+          }
+          throw laneErr;
+        }
+
+        if (!laneStartResult.lane?.run_id) {
+          throw new Error(t("errors.noRunIdReturned"));
+        }
+
+        try {
+          const fetched = await api.run.get(laneStartResult.lane.run_id);
+          setHandle(fetched);
+          refreshList();
+        } catch {
+          try {
+            await attachToRun(laneStartResult.lane.run_id);
+            refreshList();
+          } catch (fallbackErr: unknown) {
+            const attachMsg = fallbackErr instanceof Error ? fallbackErr.message : "unknown";
+            throw new Error(t("errors.runStartedButNotAttached", { message: attachMsg }));
+          }
+        }
+      } catch (err: unknown) {
+        const m = err instanceof Error ? err.message : "unknown";
+        setError(t("errors.startFailed", { message: m }));
+      } finally {
+        setBusy(null);
+      }
+    },
+    [busy, t, lanes, laneId, onLaneIdChange, onLaneCreated, attachToRun, refreshList]
+  );
+
+  const onResumeFromHistory = useCallback(
+    async (item: DashboardRunHistoryItem) => {
+      if (!item.session_id) return;
+      if (busy) return;
+      setBusy("start");
+      setError(null);
+      try {
+        let fetched: RunHandle;
+
+        if (item.cwd) {
+          const effectiveCwd = item.cwd;
+          let targetLaneId = lanes.find((l) => l.cwd === effectiveCwd)?.id;
+
+          if (!targetLaneId) {
+            const ensureResult = await api.lanes.ensure({ cwd: effectiveCwd });
+            targetLaneId = ensureResult.lane.id;
+            onLaneCreated(ensureResult.lane);
+          }
+
+          const laneStartResult = await api.lanes.action(targetLaneId, "start", {
+            prompt: "",
+            model: item.model || undefined,
+            permissionMode: item.permission_mode || undefined,
+            effort: item.effort || undefined,
+            resumeSessionId: item.session_id,
+          });
+
+          if (!laneStartResult.lane?.run_id) {
+            throw new Error("No run_id returned from lane start");
+          }
+
+          fetched = await api.run.get(laneStartResult.lane.run_id);
+          onLaneIdChange(targetLaneId);
+        } else {
+          fetched = await api.run.start({
+            laneId: 0,
+            initialPrompt: "",
+            cwd: undefined,
+            model: item.model || undefined,
+            permissionMode: item.permission_mode || undefined,
+            effort: item.effort || undefined,
+            resumeSessionId: item.session_id,
+          });
+        }
+
+        setHandle(fetched);
+        setResumeSession(null);
+        refreshList();
+      } catch (err) {
+        const msg = err instanceof Error ? err.message : "unknown";
+        setError(t("errors.startFailed", { message: msg }));
+      } finally {
+        setBusy(null);
+      }
+    },
+    [busy, refreshList, t, lanes, onLaneCreated, onLaneIdChange]
+  );
+
+  const onViewFromHistory = useCallback(
+    (item: DashboardRunHistoryItem) => {
+      if (item.session_id) void onResumeFromHistory(item);
+    },
+    [onResumeFromHistory]
+  );
+
+  const newRun = useCallback(() => {
+    setHandle(null);
+    setPrompt("");
+    setResumeSession(null);
+    setError(null);
+  }, []);
+
+  if (laneId === null && showLaneSelector) {
+    return (
+      <div data-testid="pane-empty" className="flex min-h-0 flex-1 flex-col gap-2 p-4">
+        <select
+          data-testid="pane-lane-select"
+          aria-label={tLanes("splitView.paneLaneLabel")}
+          className="rounded border border-border bg-surface-1 px-2 py-1 text-xs text-fg-secondary"
+          value=""
+          onChange={(e) => e.target.value && onLaneIdChange(Number(e.target.value))}
+        >
+          <option value="">{tLanes("splitView.pickLane")}</option>
+          {lanes.map((l) => (
+            <option key={l.id} value={l.id}>
+              {l.title || l.cwd}
+            </option>
+          ))}
+        </select>
+        <p className="text-xs text-fg-muted">{tLanes("splitView.emptyPane")}</p>
+      </div>
+    );
+  }
+
+  return (
+    <div data-testid="console-body" className="flex min-h-0 flex-1 flex-col gap-5">
+      {showLaneSelector && (
+        <select
+          data-testid="pane-lane-select"
+          aria-label={tLanes("splitView.paneLaneLabel")}
+          className="rounded border border-border bg-surface-1 px-2 py-1 text-xs text-fg-secondary"
+          value={laneId ?? ""}
+          onChange={(e) => e.target.value && onLaneIdChange(Number(e.target.value))}
+        >
+          <option value="">{tLanes("splitView.pickLane")}</option>
+          {lanes.map((l) => (
+            <option key={l.id} value={l.id}>
+              {l.title || l.cwd}
+            </option>
+          ))}
+        </select>
+      )}
+
+      <header className="flex items-start gap-3">
+        <div className="w-9 h-9 rounded-xl bg-accent/15 flex items-center justify-center flex-shrink-0">
+          <Play className="w-4.5 h-4.5 text-accent" />
+        </div>
+        <div className="min-w-0 flex-1">
+          <div className="flex items-center gap-2">
+            <h1 className="text-lg font-semibold text-fg-primary">{t("title")}</h1>
+            {wsConnected ? (
+              <span className="flex items-center gap-1.5 text-[11px] text-status-success bg-status-success/10 border border-status-success/20 px-2 py-0.5 rounded-full">
+                <span className="w-1.5 h-1.5 rounded-full bg-status-success animate-pulse-dot" />
+                {tCommon("live")}
+              </span>
+            ) : (
+              <span className="flex items-center gap-1.5 text-[11px] text-fg-secondary bg-surface-4/10 border border-border-light/20 px-2 py-0.5 rounded-full">
+                <span className="w-1.5 h-1.5 rounded-full bg-surface-4" />
+                {tCommon("offline")}
+              </span>
+            )}
+          </div>
+          <p className="text-xs text-fg-muted max-w-3xl">{t("subtitle")}</p>
+        </div>
+        <ActiveRunsSwitcher
+          activeRuns={activeRuns}
+          currentHandleId={handle?.id || null}
+          onAttach={attachToRun}
+          runHistory={runHistory}
+          externalSessions={externalSessions}
+          onResumeFromHistory={onResumeFromHistory}
+          onViewFromHistory={onViewFromHistory}
+          onRefresh={refreshList}
+        />
+      </header>
+
+      {binaryStatus && !binaryStatus.found && (
+        <div className="rounded-lg border border-status-danger/40 bg-status-danger/10 px-4 py-3 text-sm text-status-danger flex items-center gap-2">
+          <AlertCircle className="w-4 h-4 flex-shrink-0" />
+          <span>{t("binary.missing")}</span>
+        </div>
+      )}
+
+      {error && (
+        <div className="rounded-lg border border-status-danger/40 bg-status-danger/10 px-4 py-3 text-sm text-status-danger flex items-center gap-2">
+          <AlertCircle className="w-4 h-4 flex-shrink-0" />
+          <span className="flex-1 break-all">{error}</span>
+        </div>
+      )}
+
+      {!handle ? (
+        <RunSetup
+          laneId={laneId ?? 0}
+          prompt={prompt}
+          onPromptChange={setPrompt}
+          cwd={cwd}
+          onCwdChange={setCwd}
+          cwdSuggestions={cwdSuggestions}
+          model={model}
+          onModelChange={setModel}
+          permissionMode={permissionMode}
+          onPermissionModeChange={setPermissionMode}
+          effort={effort}
+          onEffortChange={setEffort}
+          binaryFound={binaryStatus?.found ?? true}
+          busy={busy === "start"}
+          onStart={onStartFromSetup}
+          activeRuns={activeRuns}
+          laneCwd={currentLane?.cwd}
+          resumeSession={resumeSession}
+          onResumeSessionChange={setResumeSession}
+          runHistory={runHistory}
+          onResumeFromHistory={onResumeFromHistory}
+        />
+      ) : (
+        <div className="flex-1 min-h-0 flex flex-col">
+          <TerminalView
+            runId={handle!.id}
+            wsBaseUrl={window.location.origin.replace(/^http/, "ws")}
+          />
+          <button
+            onClick={newRun}
+            className="mt-3 px-3 py-1.5 text-sm rounded border border-border hover:border-border-light text-fg-secondary hover:text-fg-primary transition-colors"
+          >
+            {t("actions.newRun")}
+          </button>
+        </div>
+      )}
+    </div>
+  );
+}

client/src/components/run/RunHistory.tsx

@@ -12,9 +12,16 @@
  *     status / mode chip filters, a free-text search, and the per-row Attach /
  *     Resume / View actions.
  *
- * Props only: no API call of its own. The page passes `activeRuns` and
- * `runHistory` in and gets attach / resume / view / refresh back out through
- * callbacks; the 2 s refresh ticker the modal runs just calls `onRefresh`.
+ * `externalSessions` (active Claude Code sessions this dashboard did NOT spawn —
+ * e.g. `claude` started by hand in a terminal tab) are merged in as live rows so
+ * "Active runs" counts everything actually running. They carry no tmux session
+ * the dashboard can attach to, so their only action is Resume, which spawns a
+ * fresh tmux-backed `claude --resume <session>` in that cwd.
+ *
+ * Props only: no API call of its own. The page passes `activeRuns`,
+ * `runHistory` and `externalSessions` in and gets attach / resume / view /
+ * refresh back out through callbacks; the 2 s refresh ticker the modal runs
+ * just calls `onRefresh`.
  *
  * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
  */
@@ -34,6 +41,7 @@ import {
   Eye,
 } from "lucide-react";
 import type { DashboardRunHistoryItem, RunListResponse, RunStatus } from "../../lib/api";
+import type { Session } from "../../lib/types";
 
 // Minimal StatusPill component (from deleted RunConsole)
 function StatusPill({
@@ -74,6 +82,10 @@ export interface UnifiedRunRow {
   startedAt: number;
   endedAt: number | null;
   isLive: boolean;
+  /** Live Claude Code session this dashboard did not spawn — no tmux session to
+   *  attach to, so Resume (a fresh `claude --resume` in its cwd) is the only
+   *  action. */
+  external?: boolean;
 }
 
 export function ActiveRunsSwitcher({
@@ -81,6 +93,7 @@ export function ActiveRunsSwitcher({
   currentHandleId,
   onAttach,
   runHistory,
+  externalSessions = [],
   onResumeFromHistory,
   onViewFromHistory,
   onRefresh,
@@ -89,6 +102,9 @@ export function ActiveRunsSwitcher({
   currentHandleId: string | null;
   onAttach: (id: string) => void;
   runHistory: DashboardRunHistoryItem[];
+  /** Sessions with `status: "active"` from GET /api/sessions. Remote-source and
+   *  cwd-less sessions are ignored — neither can be resumed on this machine. */
+  externalSessions?: Session[];
   onResumeFromHistory: (item: DashboardRunHistoryItem) => void;
   onViewFromHistory: (item: DashboardRunHistoryItem) => void;
   onRefresh: () => void;
@@ -111,14 +127,18 @@ export function ActiveRunsSwitcher({
     };
   }, [open]);
 
-  // Merge live in-memory handles + persistent history into one row list.
-  // Live entries dedupe past-history entries with the same id.
-  const rows: UnifiedRunRow[] = useMemo(() => {
+  // Merge live in-memory handles + persistent history + externally started
+  // sessions into one row list. Live entries dedupe past-history entries with
+  // the same id; a session id already covered by a run row is never repeated as
+  // an external row.
+  const { rows, historyItems } = useMemo(() => {
     const out: UnifiedRunRow[] = [];
     const seen = new Set<string>();
+    const seenSessions = new Set<string>();
     if (activeRuns) {
       for (const r of activeRuns.items) {
         seen.add(r.id);
+        if (r.sessionId) seenSessions.add(r.sessionId);
         out.push({
           id: r.id,
           sessionId: r.sessionId,
@@ -135,6 +155,7 @@ export function ActiveRunsSwitcher({
     for (const h of runHistory) {
       if (seen.has(h.id)) continue;
       seen.add(h.id);
+      if (h.session_id) seenSessions.add(h.session_id);
       const startedTs = new Date(h.started_at).getTime() || 0;
       const endedTs = h.ended_at ? new Date(h.ended_at).getTime() : null;
       out.push({
@@ -149,9 +170,49 @@ export function ActiveRunsSwitcher({
         isLive: h.isLive,
       });
     }
+    // Externally started sessions: shown as live rows, and mirrored as
+    // synthetic history items so the existing resume path (which only reads
+    // session_id / cwd / model) works on them unchanged.
+    const synthetic: DashboardRunHistoryItem[] = [];
+    for (const s of externalSessions) {
+      if (!s.cwd) continue;
+      if (s.source && s.source !== "local") continue;
+      if (seenSessions.has(s.id)) continue;
+      seenSessions.add(s.id);
+      synthetic.push({
+        id: `session:${s.id}`,
+        session_id: s.id,
+        cwd: s.cwd,
+        model: s.model,
+        permission_mode: null,
+        effort: null,
+        resume_session_id: null,
+        prompt_preview: s.name,
+        status: "running",
+        exit_code: null,
+        started_at: s.started_at,
+        ended_at: null,
+        isLive: true,
+      });
+      out.push({
+        id: `session:${s.id}`,
+        sessionId: s.id,
+        cwd: s.cwd,
+        model: s.model,
+        status: "running",
+        promptPreview: s.name || "",
+        startedAt: new Date(s.started_at).getTime() || 0,
+        endedAt: null,
+        isLive: true,
+        external: true,
+      });
+    }
     out.sort((a, b) => b.startedAt - a.startedAt);
-    return out;
-  }, [activeRuns, runHistory]);
+    return {
+      rows: out,
+      historyItems: synthetic.length ? [...runHistory, ...synthetic] : runHistory,
+    };
+  }, [activeRuns, runHistory, externalSessions]);
 
   const liveCount = rows.filter((r) => r.isLive).length;
   const totalCount = rows.length;
@@ -196,7 +257,7 @@ export function ActiveRunsSwitcher({
             setOpen(false);
             onViewFromHistory(item);
           }}
-          runHistory={runHistory}
+          runHistory={historyItems}
           onClose={() => setOpen(false)}
           onRefresh={onRefresh}
         />
@@ -467,8 +528,10 @@ function UnifiedRunRowView({
         hour: "2-digit",
         minute: "2-digit",
       });
-  // Without mode distinction, offer resume for any finished run with a session
-  const canResume = !!row.sessionId && !row.isLive;
+  // Without mode distinction, offer resume for any finished run with a session.
+  // An external session is live but has no attachable tmux session, so Resume
+  // (a new tmux-backed `claude --resume` in its cwd) is what it gets instead.
+  const canResume = !!row.sessionId && (!row.isLive || !!row.external);
   const canView = !!row.sessionId && !row.isLive;
   return (
     <div
@@ -484,13 +547,21 @@ function UnifiedRunRowView({
             {t("runs.liveBadge", "live")}
           </span>
         )}
+        {row.external && (
+          <span
+            className="text-[10px] font-semibold text-amber-300 bg-amber-500/10 border border-amber-500/25 px-1.5 py-0.5 rounded-full"
+            title={t("runs.externalHint")}
+          >
+            {t("runs.externalBadge")}
+          </span>
+        )}
         {isCurrent && (
           <span className="text-[10px] font-semibold text-accent bg-accent/10 border border-accent/25 px-1.5 py-0.5 rounded-full">
             {t("runs.currentBadge", "current")}
           </span>
         )}
         <span className="ml-auto inline-flex items-center gap-1.5">
-          {row.isLive && !isCurrent && (
+          {row.isLive && !row.external && !isCurrent && (
             <button
               onClick={onAttach}
               className="inline-flex items-center gap-1 rounded-md border border-status-success/40 bg-status-success/10 hover:bg-status-success/20 text-status-success px-2 py-0.5 text-[10.5px] font-medium transition-colors"
@@ -502,6 +573,7 @@ function UnifiedRunRowView({
           {canResume && (
             <button
               onClick={onResume}
+              title={row.external ? t("runs.externalHint") : undefined}
               className="inline-flex items-center gap-1 rounded-md border border-accent/40 bg-accent/15 hover:bg-accent/25 text-accent px-2 py-0.5 text-[10.5px] font-medium transition-colors"
             >
               <RotateCcw className="w-3 h-3" />

client/src/components/run/__tests__/LaneConsolePane.test.tsx

@@ -0,0 +1,147 @@
+/**
+ * @file LaneConsolePane.test.tsx
+ * @description Test suite for the LaneConsolePane component
+ * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
+ */
+
+import { describe, it, expect, vi, beforeEach } from "vitest";
+import { render, screen, fireEvent, waitFor } from "@testing-library/react";
+import { LaneConsolePane } from "../LaneConsolePane";
+import { api } from "../../../lib/api";
+import type { Lane } from "../../../lib/types";
+
+vi.mock("../TerminalView", () => ({
+  TerminalView: ({ runId }: { runId: string }) => (
+    <div data-testid="terminal-view" data-run-id={runId} />
+  ),
+}));
+
+vi.mock("../../../lib/api", () => ({
+  api: {
+    lanes: {
+      ensure: vi.fn(),
+      action: vi.fn(),
+      list: vi.fn(),
+    },
+    run: {
+      list: vi.fn().mockResolvedValue({ items: [] }),
+      history: vi.fn().mockResolvedValue({ items: [] }),
+      get: vi.fn(),
+      start: vi.fn(),
+    },
+  },
+  RUN_MODEL_CHOICES: [],
+  RUN_EFFORT_CHOICES: [],
+}));
+
+const LANE: Lane = {
+  id: 1,
+  title: "demo",
+  cwd: "/workspace/a",
+  branch: null,
+  kind: "adopted",
+  source_repo: null,
+  pipeline: "default",
+  session_id: null,
+  run_id: null,
+  stage: "idle",
+  stage_since: null,
+  status: "idle",
+  gate_decision: null,
+  ci_status: null,
+  needs_action: null,
+  links: {},
+  stages: {},
+  notes: null,
+  pipeline_name: "Default",
+  pipeline_nodes: [],
+  progress: 0,
+  stage_seconds: null,
+  last_event_seconds: null,
+  liveness: "idle" as Lane["liveness"],
+  detected_stage: null,
+  detected_signal: null,
+  slot: null,
+  ports: {},
+  active_feature_id: null,
+};
+
+function baseProps() {
+  return {
+    lanes: [LANE],
+    laneId: 1,
+    showLaneSelector: false,
+    onLaneIdChange: vi.fn(),
+    onLaneCreated: vi.fn(),
+    binaryStatus: { found: true, path: "/usr/local/bin/claude" },
+    cwdSuggestions: [],
+    activeRuns: { items: [] },
+    wsConnected: true,
+  };
+}
+
+describe("LaneConsolePane", () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+  });
+
+  it("starts a run through /api/lanes/<id>/start, not /api/run/start", async () => {
+    (api.lanes.action as ReturnType<typeof vi.fn>).mockResolvedValue({
+      lane: { ...LANE, run_id: "run-1" },
+    });
+    (api.run.get as ReturnType<typeof vi.fn>).mockResolvedValue({
+      id: "run-1",
+      laneId: 1,
+      status: "running",
+      cwd: "/workspace/a",
+      model: null,
+      permissionMode: null,
+      effort: null,
+      resumeSessionId: null,
+      sessionId: null,
+      startedAt: null,
+      promptPreview: null,
+    });
+
+    render(<LaneConsolePane {...baseProps()} />);
+
+    // Set cwd and prompt
+    const cwdInput = screen.getByPlaceholderText(/type to search/i);
+    fireEvent.change(cwdInput, { target: { value: "/workspace/a" } });
+
+    const promptTextarea = screen.getByPlaceholderText(/ask claude/i);
+    fireEvent.change(promptTextarea, { target: { value: "test prompt" } });
+
+    // Find and click the Run button (the main start button in RunSetup)
+    fireEvent.click(screen.getByRole("button", { name: /^run$/i }));
+
+    await waitFor(() =>
+      expect(api.lanes.action).toHaveBeenCalledWith(1, "start", expect.any(Object))
+    );
+    expect(api.run.start).not.toHaveBeenCalled();
+    await waitFor(() =>
+      expect(screen.getByTestId("terminal-view")).toHaveAttribute("data-run-id", "run-1")
+    );
+  });
+
+  it("shows a lane dropdown only when showLaneSelector is true", () => {
+    const { rerender } = render(<LaneConsolePane {...baseProps()} showLaneSelector />);
+    expect(screen.getByTestId("pane-lane-select")).toBeInTheDocument();
+
+    rerender(<LaneConsolePane {...baseProps()} showLaneSelector={false} />);
+    expect(screen.queryByTestId("pane-lane-select")).not.toBeInTheDocument();
+  });
+
+  it("renders RunSetup when laneId is null and showLaneSelector is false (layout-1, fresh install)", () => {
+    render(<LaneConsolePane {...baseProps()} laneId={null} showLaneSelector={false} />);
+    expect(screen.getByTestId("console-body")).toBeInTheDocument();
+    expect(screen.queryByTestId("pane-empty")).not.toBeInTheDocument();
+  });
+
+  it("renders an empty placeholder with selector when laneId is null but showLaneSelector is true (split-view)", () => {
+    render(<LaneConsolePane {...baseProps()} laneId={null} showLaneSelector={true} />);
+    expect(screen.getByTestId("pane-empty")).toBeInTheDocument();
+    expect(screen.getByTestId("pane-lane-select")).toBeInTheDocument();
+    expect(screen.queryByTestId("console-body")).not.toBeInTheDocument();
+  });
+});

client/src/components/run/__tests__/RunHistory.test.tsx

@@ -17,6 +17,7 @@ import { beforeEach, describe, expect, it, vi } from "vitest";
 import i18n from "i18next";
 import { ActiveRunsSwitcher, RunsModal, type UnifiedRunRow } from "../RunHistory";
 import type { DashboardRunHistoryItem, RunListResponse } from "../../../lib/api";
+import type { Session } from "../../../lib/types";
 
 const LIVE_ID = "run-live";
 const PAST_ID = "run-past";
@@ -67,6 +68,21 @@ const HEADLESS = historyItem({
   started_at: new Date(1000).toISOString(),
 });
 
+function externalSession(over: Partial<Session> = {}): Session {
+  return {
+    id: "sess-external",
+    name: "the external prompt",
+    status: "active",
+    cwd: "/tmp/external",
+    model: "claude-opus-5",
+    started_at: new Date(3000).toISOString(),
+    ended_at: null,
+    updated_at: new Date(3000).toISOString(),
+    source: "local",
+    ...over,
+  } as unknown as Session;
+}
+
 function renderSwitcher(overrides: Partial<React.ComponentProps<typeof ActiveRunsSwitcher>> = {}) {
   const spies = {
     onAttach: vi.fn(),
@@ -188,6 +204,44 @@ describe("ActiveRunsSwitcher", () => {
     expect(screen.queryByText("stale copy")).toBeNull();
   });
 
+  it("counts and lists a session started outside the dashboard, resumable not attachable", () => {
+    const { spies } = renderSwitcher({
+      activeRuns: null,
+      runHistory: [],
+      externalSessions: [externalSession()],
+    });
+    fireEvent.click(screen.getByText(i18n.t("run:runs.viewActive_other", { count: 1 })));
+    expect(screen.getByText("the external prompt")).toBeTruthy();
+    expect(screen.getByText(i18n.t("run:runs.externalBadge"))).toBeTruthy();
+    // No tmux session of ours to attach to — Resume is the only action.
+    expect(screen.queryByText(i18n.t("run:runs.attachLabel", "Attach"))).toBeNull();
+    fireEvent.click(screen.getByText(i18n.t("run:resume.resumeOption")));
+    expect(spies.onResumeFromHistory).toHaveBeenCalledWith(
+      expect.objectContaining({
+        id: "session:sess-external",
+        session_id: "sess-external",
+        cwd: "/tmp/external",
+        status: "running",
+        isLive: true,
+      })
+    );
+  });
+
+  it("skips external sessions already covered by a run, remote ones, and cwd-less ones", () => {
+    renderSwitcher({
+      runHistory: [],
+      externalSessions: [
+        externalSession({ id: "sess-live" }), // same session as the live run
+        externalSession({ id: "sess-remote", source: "remote-1" }),
+        externalSession({ id: "sess-nocwd", cwd: null }),
+      ],
+    });
+    fireEvent.click(screen.getByText(i18n.t("run:runs.viewActive_other", { count: 1 })));
+    expect(screen.getByText("the live prompt")).toBeTruthy();
+    expect(screen.queryByText("the external prompt")).toBeNull();
+    expect(screen.queryByText(i18n.t("run:runs.externalBadge"))).toBeNull();
+  });
+
   it("fires attach with the run id of the row that was clicked", () => {
     const { spies } = renderSwitcher();
     openModal();

client/src/i18n/locales/en/lanes.json

@@ -90,6 +90,8 @@
   "git.uncommitted": "{{dirty}} modified · {{untracked}} untracked",
   "kind.adopted": "adopted",
   "kind.managed": "managed",
+  "laneDetail.hide": "Hide details",
+  "laneDetail.show": "Lane details",
   "laneHeader": "Lane {{id}} · {{title}} · {{pipeline}}",
   "locks.held_one": "{{count}} lock held",
   "locks.held_other": "{{count}} locks held",
@@ -120,6 +122,10 @@
   "features.archived": "archived",
   "features.viewingArchived": "Viewing archived feature \"{{slug}}\" — the lane keeps running; this is a read-only snapshot.",
   "proof.ticketReport": "Task report",
+  "splitView.emptyPane": "No lane selected for this pane.",
+  "splitView.paneLaneLabel": "Pane lane selector",
+  "splitView.paneCount": "{{count}} pane",
+  "splitView.pickLane": "Pick a lane",
   "statusDead": "DEAD",
   "title": "Lanes",
   "tooltipStart": "Spawn a conversation-mode run with no initial prompt; driven from CLI or via message"

client/src/i18n/locales/en/run.json

@@ -116,7 +116,9 @@
   "runs": {
     "allSessionsLink": "See all Claude Code sessions →",
     "attached": "Attached to existing run",
-    "scopeNote": "Only shows runs you started from this dashboard.",
+    "externalBadge": "external",
+    "externalHint": "Started outside the dashboard, so there is no terminal to attach to. Resume opens a new tmux-backed `claude --resume` of this session in its folder.",
+    "scopeNote": "Runs started from this dashboard, plus Claude Code sessions running outside it.",
     "started": "Started {{when}}",
     "switcher": "Active runs",
     "switcherEmpty": "No active runs",

client/src/i18n/locales/vi/lanes.json

@@ -90,6 +90,8 @@
   "git.uncommitted": "{{dirty}} đã sửa · {{untracked}} chưa theo dõi",
   "kind.adopted": "đã nhận",
   "kind.managed": "được quản lý",
+  "laneDetail.hide": "Ẩn chi tiết",
+  "laneDetail.show": "Chi tiết lane",
   "laneHeader": "Làn đường {{id}} · {{title}} · {{pipeline}}",
   "locks.held_one": "Đang giữ {{count}} khóa",
   "locks.held_other": "Đang giữ {{count}} khóa",
@@ -120,6 +122,10 @@
   "features.archived": "đã lưu trữ",
   "features.viewingArchived": "Xem tính năng đã lưu trữ \"{{slug}}\" — lane tiếp tục chạy; đây là ảnh chụp nhanh chỉ đọc.",
   "proof.ticketReport": "Báo cáo nhiệm vụ",
+  "splitView.emptyPane": "Chưa chọn lane cho ô này.",
+  "splitView.paneLaneLabel": "Bộ chọn lane cho ô",
+  "splitView.paneCount": "{{count}} ô",
+  "splitView.pickLane": "Chọn lane",
   "statusDead": "ĐÃ CHẾT",
   "title": "Làn đường",
   "tooltipStart": "Tạo một lần chạy ở chế độ hội thoại mà không có lời nhắc ban đầu; được điều khiển từ CLI hoặc qua tin nhắn"

client/src/i18n/locales/vi/run.json

@@ -115,7 +115,9 @@
   "runs": {
     "allSessionsLink": "Xem tất cả phiên Claude Code →",
     "attached": "Đã gắn vào run đang chạy",
-    "scopeNote": "Chỉ hiển thị các run bạn khởi chạy từ dashboard này.",
+    "externalBadge": "ngoài dashboard",
+    "externalHint": "Phiên này khởi chạy ngoài dashboard nên không có terminal để attach. Resume sẽ mở một `claude --resume` mới trong tmux tại đúng thư mục đó.",
+    "scopeNote": "Các run khởi chạy từ dashboard này, cùng những phiên Claude Code đang chạy bên ngoài.",
     "started": "Bắt đầu lúc {{when}}",
     "switcher": "Run đang chạy",
     "switcherEmpty": "Không có run đang chạy",

client/src/lib/__tests__/splitViewStorage.test.ts

@@ -0,0 +1,44 @@
+/**
+ * @file splitViewStorage.test.ts
+ * @description Tests for the splitViewStorage module.
+ * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
+ */
+
+import { describe, it, expect, beforeEach } from "vitest";
+import {
+  readSplitViewState,
+  writeSplitViewState,
+  defaultSplitViewState,
+} from "../splitViewStorage";
+
+describe("splitViewStorage", () => {
+  beforeEach(() => {
+    localStorage.clear();
+  });
+
+  it("returns the default state when nothing is stored", () => {
+    expect(readSplitViewState()).toEqual(defaultSplitViewState());
+  });
+
+  it("defaults to a single unselected pane", () => {
+    expect(defaultSplitViewState()).toEqual({ layout: 1, paneLaneIds: [null] });
+  });
+
+  it("round-trips a written state", () => {
+    writeSplitViewState({ layout: 4, paneLaneIds: [1, 2, null, null] });
+    expect(readSplitViewState()).toEqual({ layout: 4, paneLaneIds: [1, 2, null, null] });
+  });
+
+  it("falls back to the default when stored JSON is malformed", () => {
+    localStorage.setItem("ccam.workspace.splitView", "{not json");
+    expect(readSplitViewState()).toEqual(defaultSplitViewState());
+  });
+
+  it("falls back to the default when the stored layout is not 1, 2, or 4", () => {
+    localStorage.setItem(
+      "ccam.workspace.splitView",
+      JSON.stringify({ layout: 3, paneLaneIds: [] })
+    );
+    expect(readSplitViewState()).toEqual(defaultSplitViewState());
+  });
+});

client/src/lib/splitViewStorage.ts

@@ -0,0 +1,54 @@
+/**
+ * @file splitViewStorage.ts
+ * @description Persists the Workspace page's split-terminal layout (1/2/4
+ * panes) and each pane's chosen lane id to localStorage, so the layout
+ * survives a page reload. Follows the same read/write-with-fallback
+ * convention as useTheme.ts.
+ * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
+ */
+
+export type SplitLayout = 1 | 2 | 4;
+
+export interface SplitViewState {
+  layout: SplitLayout;
+  paneLaneIds: (number | null)[];
+}
+
+const STORAGE_KEY = "ccam.workspace.splitView";
+
+export function defaultSplitViewState(): SplitViewState {
+  return { layout: 1, paneLaneIds: [null] };
+}
+
+function isValidLayout(value: unknown): value is SplitLayout {
+  return value === 1 || value === 2 || value === 4;
+}
+
+function isValidState(value: unknown): value is SplitViewState {
+  if (!value || typeof value !== "object") return false;
+  const v = value as Record<string, unknown>;
+  return (
+    isValidLayout(v.layout) &&
+    Array.isArray(v.paneLaneIds) &&
+    v.paneLaneIds.every((id) => id === null || typeof id === "number")
+  );
+}
+
+export function readSplitViewState(): SplitViewState {
+  try {
+    const raw = localStorage.getItem(STORAGE_KEY);
+    if (!raw) return defaultSplitViewState();
+    const parsed: unknown = JSON.parse(raw);
+    return isValidState(parsed) ? parsed : defaultSplitViewState();
+  } catch {
+    return defaultSplitViewState();
+  }
+}
+
+export function writeSplitViewState(state: SplitViewState): void {
+  try {
+    localStorage.setItem(STORAGE_KEY, JSON.stringify(state));
+  } catch {
+    /* ignore quota / disabled storage */
+  }
+}

client/src/pages/__tests__/Workspace.test.tsx

@@ -7,7 +7,7 @@
  */
 
 import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
-import { render, act, screen, waitFor } from "@testing-library/react";
+import { render, act, screen, waitFor, fireEvent } from "@testing-library/react";
 import { MemoryRouter } from "react-router-dom";
 import userEvent from "@testing-library/user-event";
 
@@ -633,3 +633,58 @@ describe("Workspace — proof gallery", () => {
     expect(gallery).toBeNull();
   });
 });
+
+describe("split terminal view", () => {
+  beforeEach(() => {
+    localStorage.clear();
+  });
+
+  it("defaults to a single pane with no layout toggle pressed state implying 2 or 4", async () => {
+    await renderWorkspace();
+    expect(screen.getAllByTestId("console-body")).toHaveLength(1);
+    expect(screen.queryAllByTestId("pane-lane-select")).toHaveLength(0);
+  });
+
+  it("switching to 2-pane layout renders two independent panes with lane pickers", async () => {
+    await renderWorkspace();
+    fireEvent.click(screen.getByRole("button", { name: /2.*pane/i }));
+    await settle();
+    expect(screen.getAllByTestId(/console-body|pane-empty/)).toHaveLength(2);
+    expect(screen.getAllByTestId("pane-lane-select")).toHaveLength(2);
+  });
+
+  it("switching to 4-pane layout renders four panes", async () => {
+    await renderWorkspace();
+    fireEvent.click(screen.getByRole("button", { name: /4.*pane/i }));
+    await settle();
+    expect(screen.getAllByTestId(/console-body|pane-empty/)).toHaveLength(4);
+  });
+
+  it("persists the layout and pane selections to localStorage across remounts", async () => {
+    const { unmount } = await renderWorkspace();
+    fireEvent.click(screen.getByRole("button", { name: /2.*pane/i }));
+    await settle();
+    const selects = screen.getAllByTestId("pane-lane-select");
+    const select = selects[1];
+    expect(select).toBeDefined();
+    fireEvent.change(select!, { target: { value: String(lanesToReturn[1]!.id) } });
+    await settle();
+    unmount();
+
+    await renderWorkspace();
+    const persistedSelects = screen.getAllByTestId("pane-lane-select");
+    expect(persistedSelects).toHaveLength(2);
+    expect((persistedSelects[1] as HTMLSelectElement).value).toBe(String(lanesToReturn[1]!.id));
+  });
+
+  it("falls back to unselected when a persisted lane id no longer exists", async () => {
+    localStorage.setItem(
+      "ccam.workspace.splitView",
+      JSON.stringify({ layout: 2, paneLaneIds: [9999, null] })
+    );
+    await renderWorkspace();
+    // Lane 9999 doesn't exist, so it falls back to null (unselected).
+    // The second pane is already null. Both render as pane-empty.
+    expect(screen.getAllByTestId("pane-empty")).toHaveLength(2);
+  });
+});

client/src/pages/__tests__/__snapshots__/screens.snapshot.test.tsx.snap

@@ -5762,7 +5762,10 @@ exports[`screen snapshots > Run 1`] = `
       </button>
     </div>
     <div
-      class="flex snap-x snap-mandatory gap-2 overflow-x-auto pb-1"
+      class="flex min-h-0 flex-1 gap-4"
+    >
+      <div
+        class="flex w-60 shrink-0 flex-col gap-2 overflow-y-auto pr-1"
         data-testid="lane-strip"
       >
         <p
@@ -5776,8 +5779,33 @@ exports[`screen snapshots > Run 1`] = `
         </p>
       </div>
       <div
-      class="flex min-h-0 flex-col gap-2"
+        class="flex min-h-0 flex-1 flex-col gap-2"
       >
+        <div
+          class="flex items-center gap-1.5"
+        >
+          <button
+            aria-pressed="true"
+            class="rounded border px-2 py-1 text-xs border-accent bg-accent/15 text-accent"
+            type="button"
+          >
+            1 pane
+          </button>
+          <button
+            aria-pressed="false"
+            class="rounded border px-2 py-1 text-xs border-border text-fg-secondary hover:border-border-light"
+            type="button"
+          >
+            2 pane
+          </button>
+          <button
+            aria-pressed="false"
+            class="rounded border px-2 py-1 text-xs border-border text-fg-secondary hover:border-border-light"
+            type="button"
+          >
+            4 pane
+          </button>
+        </div>
         <div
           class="flex min-h-0 flex-1 flex-col gap-5"
           data-testid="console-body"
@@ -6111,6 +6139,7 @@ exports[`screen snapshots > Run 1`] = `
         </div>
       </div>
     </div>
+  </div>
 </div>
 `;
 

docs/LANES.md

@@ -310,10 +310,23 @@ The dashboard web UI merges lanes and runs into a single **Workspace** page acce
 - **Header** — the page title and four counters (`lanes`, `running`, `needs you`, `dead`), plus Add lane. The `needs you` and `dead` counters appear only when they are non-zero, so a quiet header means nothing is waiting on a human.
 - **Detail panel** — the selected lane's declared stage, its inferred stage when detection leads, a full-width pipeline map, and a legend naming all five node states plus the dashed-amber inferred treatment.
 - **Terminal** — a real interactive terminal (xterm.js) displaying the tmux session's PTY output, with full support for interactive commands, editors, and pagers. A live run keeps its rendered history and scroll position when scrolling.
+- **Split view** — a layout toggle (1 / 2 / 4 panes) renders that many independent terminal panes side by side (`grid-cols-2` for 2, a 2×2 grid for 4). Layout 1 is bound to the lane strip's selection, same as always; layouts 2 and 4 give each pane its own lane picker, independent of the strip. The chosen layout and each pane's lane persist to `localStorage` (`ccam.workspace.splitView`) across reloads.
 - **Lane grid** — one card per lane, 1 column, 2 at `md`, 3 at `xl`. Each card carries the lane id, liveness dot and status, title, declared stage with a progress bar and time-on-stage, the `auto:` chip when detection leads, the kind and CI tags, the working-copy facts from `GET /api/lanes/:id/git`, the needs-you banner, and the action row.
 
 Run history is per lane, queryable via `GET /api/run/history?laneId=<n>`.
 
+### Active runs list
+
+The **Active runs** button in the console header opens the merged run list. It shows three sources in one place, newest first:
+
+1. live in-memory tmux runs from `GET /api/run`,
+2. persisted dashboard runs from `GET /api/run/history`,
+3. Claude Code sessions running **outside** the dashboard — `GET /api/sessions?status=active`, i.e. a `claude` the user started by hand in a terminal tab. These carry an amber `external` badge, and the button's live count includes them, so two hand-started agents read as "2 active runs".
+
+An external session is deduped against a dashboard run with the same `session_id`, and sessions from a remote data source (`source !== "local"`) or without a `cwd` are skipped — neither can be resumed on this machine.
+
+External rows have **no Attach action**: the dashboard owns no tmux session for them, so there is no PTY to bridge. Their action is **Resume**, which does what resuming from history does — `POST /api/lanes/ensure` for the session's `cwd`, then `POST /api/lanes/:id/start` with `resumeSessionId` — spawning a *new* tmux-backed `claude --resume <session>` in that folder. The original terminal keeps running; resuming gives you a second Claude Code process on the same transcript, not a view of the first one.
+
 The UI operates on a working directory (`cwd`), not a lane id. Starting a run in a `cwd` that no lane owns calls `POST /api/lanes/ensure` first, to idempotently find or adopt a lane for that path; a `cwd` an existing lane already owns is matched from the loaded lane list without a round trip. Either way the run is then started through `POST /api/lanes/:id/start` rather than directly through `POST /api/run`.
 
 ### Finding or adopting a lane: `POST /api/lanes/ensure`

docs/superpowers/specs/2026-08-14-split-terminal-view-design.md

@@ -0,0 +1,74 @@
+# Split terminal view for the Workspace console
+
+**Status:** approved 2026-08-14.
+
+## Problem
+
+`Workspace.tsx` renders exactly one lane's run console at a time: a single
+`RunSetup`/`TerminalView` switcher (client/src/pages/Workspace.tsx:789-824)
+driven by page-level state (`selectedLaneId`, `prompt`, `cwd`, `model`,
+`permissionMode`, `effort`, `resumeSession`, `handle`, `busy`, `activeRuns`,
+`runHistory`, `cwdSuggestions`). Lanes are independent working directories
+that can each have their own live tmux/PTY session running concurrently on
+the server (`server/lib/pty-attach.js`), but the dashboard can only show one
+at a time — comparing two lanes' output means switching back and forth.
+
+The user wants to view multiple lanes' terminals side by side: 1 pane (today's
+behavior), 2 panes (left/right), or 4 panes (2x2 grid).
+
+## Approach
+
+**Extract a self-contained `LaneConsolePane` component.** Move the existing
+RunSetup/TerminalView switcher and all its state out of `Workspace.tsx` into
+its own component that owns one lane's run lifecycle independently. Each
+pane gets its own `laneId` (chosen via a dropdown in the pane header, listing
+all lanes, not just ones with an active run) and manages its own
+prompt/cwd/model/permissionMode/effort/resumeSession/handle/busy/activeRuns/
+runHistory state — nothing is shared across panes.
+
+Workspace keeps a `paneLaneIds: (number | null)[]` array sized to the current
+layout (1, 2, or 4) and renders that many `LaneConsolePane` instances in a
+CSS grid. This is the only viable approach given the existing state model is
+single-lane; the alternative (keeping one shared state object indexed by
+lane) would require rewriting every handler in Workspace.tsx to be
+lane-aware and is a much larger, riskier diff for the same result.
+
+## Layout
+
+A layout toggle (1 / 2 / 4 buttons) sits next to the existing console
+header. Grid via CSS:
+
+- **1**: full width — identical to today.
+- **2**: `grid-cols-2` — left/right.
+- **4**: `grid-cols-2 grid-rows-2` — four corners.
+
+Each pane has a small header with a lane-select dropdown. If the selected
+lane has no active run, the pane shows a compact `RunSetup` (reused
+component, same as today's pre-run form) so the user can start one directly
+from the pane. If it has an active run, the pane shows `TerminalView` as
+today.
+
+## Persistence
+
+The chosen layout mode and each pane's selected `laneId` are saved to
+`localStorage` (e.g. key `ccam.workspace.splitView`) and restored on next
+visit to Workspace. If a persisted lane no longer exists, that pane falls
+back to unselected (dropdown placeholder).
+
+## Non-goals
+
+- No server/API changes — this is purely a client-side rendering feature.
+  Each lane's run already exists independently server-side; this just lets
+  the UI display more than one at once.
+- No synchronized input across panes (typing in one pane's terminal does not
+  affect others) — each `TerminalView` keeps its own independent WebSocket
+  connection, unchanged from today's single-instance behavior.
+
+## Testing
+
+- `client/src/pages/__tests__/Workspace.test.tsx` currently mocks
+  `TerminalView` and exercises the single-console flow; update it (or add a
+  sibling test file) to cover: layout toggle, per-pane lane dropdown,
+  starting a run from within a pane, and multiple panes rendering
+  independent `TerminalView`/`RunSetup` instances.
+- Run `npm run test:client` before considering this done.

server/__tests__/lane-lifecycle.test.js

@@ -80,6 +80,29 @@ function makeRunChild({ exitsOnKill }) {
   return child;
 }
 
+// Puts a fake `claude` binary on PATH so a real `/start` spawns a real tmux
+// session running THIS script instead of the system Claude Code CLI. Tests
+// that mock tmux's own exec calls (to simulate a stuck/live session) still
+// spawn this real process underneath — without the stub, that spawn launches
+// the actual `claude` binary and, because the mock replaces the app's own
+// kill-session call, the real process is never actually terminated, leaking
+// a live tmux session + CLI process for good. Returns the restore function.
+function stubClaudeBinary(name) {
+  const bin = path.join(ROOT, `${name}-bin`);
+  const claude = path.join(bin, "claude");
+  fs.mkdirSync(bin, { recursive: true });
+  fs.writeFileSync(
+    claude,
+    "#!/usr/bin/env node\nprocess.on('SIGTERM', () => process.exit(0));\nsetInterval(() => {}, 1000);\n"
+  );
+  fs.chmodSync(claude, 0o755);
+  const originalPath = process.env.PATH;
+  process.env.PATH = `${bin}${path.delimiter}${originalPath}`;
+  return () => {
+    process.env.PATH = originalPath;
+  };
+}
+
 async function waitForProvisioning(id) {
   const deadline = Date.now() + 5000;
   let response;
@@ -818,6 +841,7 @@ describe("destructive lane lifecycle actions", () => {
     fs.writeFileSync(sentinel, "still here\n");
 
     // Start a run for the lane
+    const restorePath = stubClaudeBinary("await-timeout");
     const started = await request("POST", `/api/lanes/${lane.id}/start`, { prompt: "stuck" });
     assert.equal(started.status, 200);
     const runId = started.body.lane.run_id;
@@ -848,6 +872,15 @@ describe("destructive lane lifecycle actions", () => {
       assert.equal(fs.readFileSync(sentinel, "utf8"), "still here\n");
     } finally {
       tmux.__reset();
+      // The mocked kill-session above only fools the app's own check — the
+      // real tmux session + claude stub spawned above is still alive and
+      // must be killed for real, or it leaks past this test run.
+      try {
+        execFileSync("tmux", ["kill-session", "-t", runId], { stdio: "ignore" });
+      } catch {
+        // already gone
+      }
+      restorePath();
     }
     await request("DELETE", `/api/lanes/${lane.id}`);
   });
@@ -889,6 +922,7 @@ describe("destructive lane lifecycle actions", () => {
     const lane = await createManagedLane("start-twice");
 
     // Start a run for the lane
+    const restorePath = stubClaudeBinary("start-twice");
     const started = await request("POST", `/api/lanes/${lane.id}/start`, { prompt: "first" });
     assert.equal(started.status, 200);
     const runId = started.body.lane.run_id;
@@ -915,6 +949,15 @@ describe("destructive lane lifecycle actions", () => {
       assert.equal(after.body.lane.run_id, runId);
     } finally {
       tmux.__reset();
+      // The real tmux session behind the "first" run is never reset/killed
+      // in this test, mocked or otherwise — kill it for real so it doesn't
+      // leak past this test run.
+      try {
+        execFileSync("tmux", ["kill-session", "-t", runId], { stdio: "ignore" });
+      } catch {
+        // already gone
+      }
+      restorePath();
     }
 
     await request("DELETE", `/api/lanes/${lane.id}`);
@@ -1134,6 +1177,7 @@ describe("lane ensure, start mode, lane_id and releasing a finished run", () =>
     const lane = await adoptedLane("release-moved-on");
 
     // Create a run for this lane.
+    const restorePath = stubClaudeBinary("release-moved-on");
     const started = await request("POST", `/api/lanes/${lane.id}/start`, { prompt: "test" });
     assert.equal(started.status, 200, JSON.stringify(started.body));
     const runId = started.body.lane.run_id;
@@ -1161,6 +1205,14 @@ describe("lane ensure, start mode, lane_id and releasing a finished run", () =>
       assert.equal(after.status, "running");
     } finally {
       tmux.__reset();
+      // The app never calls kill-session here (healing preserves the "live"
+      // run) — kill the real tmux session directly so it doesn't leak.
+      try {
+        execFileSync("tmux", ["kill-session", "-t", runId], { stdio: "ignore" });
+      } catch {
+        // already gone
+      }
+      restorePath();
     }
   });
 
@@ -1169,6 +1221,7 @@ describe("lane ensure, start mode, lane_id and releasing a finished run", () =>
     const lane = await adoptedLane("release-stale-run");
 
     // Start a run for this lane.
+    const restorePath = stubClaudeBinary("release-stale-run");
     const started = await request("POST", `/api/lanes/${lane.id}/start`, { prompt: "test" });
     assert.equal(started.status, 200, JSON.stringify(started.body));
     const runId = started.body.lane.run_id;
@@ -1195,6 +1248,14 @@ describe("lane ensure, start mode, lane_id and releasing a finished run", () =>
       assert.equal(after.status, "idle", "status should be idle after run is gone");
     } finally {
       tmux.__reset();
+      // The app believes the session is already gone and never calls
+      // kill-session — kill the real tmux session directly so it doesn't leak.
+      try {
+        execFileSync("tmux", ["kill-session", "-t", runId], { stdio: "ignore" });
+      } catch {
+        // already gone
+      }
+      restorePath();
     }
   });
 });