feat(workspace): AI tool per session, one place to start a session, ended sessions open like Claude Desktop

- A session picks its own AI tool: `tool` on POST /api/lanes/:id/start
  (a catalog id, known + enabled, else 400 EBADTOOL/EDISABLED); a resume
  keeps the tool its session ran on (`sessions.tool`). The workspace's
  `lanes.tool` is now only the default.
- The workspace home's prompt box is the one place a session starts. Its
  fields run in order: AI → AI Router (Native or a profile) → Model (the
  tool's own list, or the router's models) → Permission (Claude mode /
  Codex sandbox+approval / catalog bypass) → Effort.
- The pane's run form (RunSetup) is gone: New run, a single pane's exit and
  an empty split pane's New session all go to the home. RunSetup.tsx keeps
  PromptEditor, CwdAutocomplete and ModelPicker (new `choices` prop).
- The tool icon moved from the sidebar's workspace row to each session row
  (right edge, `session.tool`); the split-pane header shows the run's tool.
- An ended session opens in its workspace (`&session=`, SessionReplay.tsx):
  its conversation read-only plus a prompt box; only a SENT message resumes
  it (resumeSessionId + prompt, first free slot). The console is only
  hidden behind it.
- Analyst button beside Files/Changes in the right panel opens
  /sessions/:id for the opened session.
- Gemini CLI ships its own icon (client/public/ai-tools/gemini.svg, from
  zonalogo.com).
- RouterPicker always shows (Native disabled for tools without router
  support); useAiRouters() exported.
- Tests: server start-with-tool cases; SessionReplay, home field order/tool/
  router models, empty pane, Analyst; dropped the cwd-field suites
  (Run.defaultCwd, Workspace.laneCwd). Docs: CLAUDE.md rules, API.md,
  LANES.md, README, ARCHITECTURE, INSTALL.

client/src/components/lanes/SessionReplay.tsx

@@ -0,0 +1,116 @@
+/**
+ * @file SessionReplay — an ENDED session opened in its workspace
+ * (`/workspace?lane=<id>&session=<sessionId>`), the way Claude Desktop opens
+ * an old one: its conversation, read-only (`ConversationView`), and a prompt
+ * box under it. Opening it resumes nothing; only SENDING a message does —
+ * `POST /api/lanes/:id/start` with `resumeSessionId` and that prompt, in the
+ * first free pane slot, after which `onResumed` opens the pane (`&run=`). The
+ * session's tool and folder come from its row (`GET /api/sessions/:id`), so a
+ * resume runs on the tool the session ran on (the server enforces that too).
+ * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
+ */
+
+import { useEffect, useState } from "react";
+import { useTranslation } from "react-i18next";
+import { Send } from "lucide-react";
+import { api, type RunHandle } from "../../lib/api";
+import type { Lane, Session } from "../../lib/types";
+import { ConversationView } from "../conversation/ConversationView";
+import { PromptEditor } from "../run/RunSetup";
+import { freeSlot, paneRunId } from "./WorkspaceHome";
+
+export function SessionReplay({
+  lane,
+  sessionId,
+  liveRuns,
+  onResumed,
+}: {
+  lane: Lane;
+  sessionId: string;
+  /** Every live dashboard pane, to pick a free slot. */
+  liveRuns: RunHandle[];
+  /** Opens the pane the resume started in. */
+  onResumed: (runId: string) => void;
+}) {
+  const { t } = useTranslation("lanes");
+  const [session, setSession] = useState<Session | null>(null);
+  const [prompt, setPrompt] = useState("");
+  const [busy, setBusy] = useState(false);
+  const [error, setError] = useState<string | null>(null);
+
+  useEffect(() => {
+    let live = true;
+    setSession(null);
+    setPrompt("");
+    setError(null);
+    api.sessions
+      .get(sessionId)
+      .then((r) => live && setSession(r.session))
+      .catch(() => undefined);
+    return () => {
+      live = false;
+    };
+  }, [sessionId]);
+
+  const send = async () => {
+    const text = prompt.trim();
+    if (!text || busy) return;
+    const slot = freeSlot(lane.id, liveRuns);
+    if (slot === null) {
+      setError(t("home.allBusy"));
+      return;
+    }
+    setBusy(true);
+    setError(null);
+    try {
+      const r = await api.lanes.action(lane.id, "start", {
+        slot,
+        resumeSessionId: sessionId,
+        prompt: text,
+      });
+      setPrompt("");
+      onResumed(r.run_id ?? paneRunId(lane.id, slot));
+    } catch (err) {
+      setError(err instanceof Error ? err.message : String(err));
+    } finally {
+      setBusy(false);
+    }
+  };
+
+  return (
+    <div data-testid="session-replay" className="flex min-h-0 flex-1 flex-col gap-2">
+      <div className="min-h-0 flex-1 overflow-hidden">
+        <ConversationView sessionId={sessionId} />
+      </div>
+      <div className="rounded-xl border border-border bg-surface-1 p-2">
+        <PromptEditor
+          value={prompt}
+          onChange={setPrompt}
+          onSubmit={() => void send()}
+          placeholder={t("replay.placeholder")}
+          rows={2}
+          slash={(session?.tool ?? "claude") === "claude"}
+          fileCwd={session?.cwd || lane.cwd}
+        />
+        <div className="mt-1 flex items-center gap-2">
+          <span className="text-[11px] text-fg-muted">{t("replay.hint")}</span>
+          <button
+            type="button"
+            data-testid="session-replay-send"
+            onClick={() => void send()}
+            disabled={busy || !prompt.trim()}
+            className="btn-primary ml-auto text-xs disabled:opacity-50"
+          >
+            <Send className="h-3.5 w-3.5" />
+            {t("replay.send")}
+          </button>
+        </div>
+        {error && (
+          <p role="alert" className="mt-1 text-xs text-status-danger">
+            {error}
+          </p>
+        )}
+      </div>
+    </div>
+  );
+}