feat: AI commit messages, change tree, router behavesAs, sidebar times (v2.2.0)

- Changes panel: Files and Changes merged into one panel; the overview's
  groups drawn as a folder tree (compacted chains, file counts, fold,
  stage/unstage a whole folder)
- AI-suggested commit message for what is staged
  (POST /api/lanes/:id/git/commit-message, claude -p --safe-mode, haiku)
- AI Router: optional "Behaves as" Claude model id, written as
  modelPicker options into the router's --settings file (issue #56)
- Sidebar: session rows show last activity, live rows their start time;
  a closed Terminal row can be removed (DELETE /api/run/history/:id)
- Every pane's CLI starts only once a client is attached; claude panes
  no longer forced inline; tmux scrollbar one column wide
- Update notifier: "Check for updates" reopens a closed notice

client/src/components/lanes/WorkspaceSessionList.tsx

@@ -14,7 +14,8 @@
  * **New session** from the run itself, and a live Terminal tab (`tool: "shell"`,
  * which never has a session) as **Terminal** — and under the sessions the last
  * `CLOSED_TERMINALS` closed ones (`GET /api/run/history?tool=shell`), whose
- * click opens a NEW shell tab (a shell cannot be resumed); Ctrl/Cmd+click opens
+ * click opens a NEW shell tab (a shell cannot be resumed) and whose hover X or
+ * right-click menu forgets the row (`DELETE /api/run/history/:id`); Ctrl/Cmd+click opens
  * it in a split beside the focused pane) — attaching, never starting or
  * resuming anything;
  * any other session opens in its workspace too (`?lane=<id>&session=<id>`,
@@ -31,7 +32,7 @@
 import { useEffect, useState, type ReactNode } from "react";
 import { confirmDialog } from "../../lib/confirm";
 import { isSubmitEnter } from "../../lib/keys";
-import { Archive, GitBranch, SquareTerminal } from "lucide-react";
+import { Archive, GitBranch, SquareTerminal, X } from "lucide-react";
 import { useTranslation } from "react-i18next";
 import { Link, useNavigate } from "react-router-dom";
 import { api, type RunHandle, type RunHistoryItem } from "../../lib/api";
@@ -42,7 +43,7 @@ import { timeAgo } from "../../lib/format";
 import { ConfirmModal } from "../ConfirmModal";
 import { AiToolIcon } from "../AiToolIcon";
 import { useAiTools } from "../../hooks/useAiTools";
-import { useContextMenu } from "../ContextMenu";
+import { ContextMenu, MenuItem, MenuSeparator, useContextMenu } from "../ContextMenu";
 import { SessionMenu } from "./SessionMenu";
 
 export const SESSION_LIMIT = 6;
@@ -297,6 +298,15 @@ export function WorkspaceSessionList({
       toast.error(err);
     }
   };
+  const closedCtx = useContextMenu<RunHistoryItem>();
+  const forgetShell = async (r: RunHistoryItem) => {
+    try {
+      await api.run.forgetHistory(r.id);
+      setClosedShells((all) => all.filter((x) => x.id !== r.id));
+    } catch (err) {
+      toast.error(err);
+    }
+  };
   const own = useSessionPage({ lane: lane.id, archived: false, limit }, refreshKey);
   const sessions = own?.sessions ?? (own === null ? null : []);
   const more = own ? Math.max(0, own.total - own.sessions.length) : 0;
@@ -458,19 +468,19 @@ export function WorkspaceSessionList({
             >
               <span aria-hidden className="h-1.5 w-1.5 shrink-0 rounded-full bg-status-success" />
               <span className="sr-only">{t("tree.state.live")}</span>
+              <span className={`truncate ${r.tool === "shell" ? "" : "italic"}`}>
+                {r.tool === "shell" ? t("tabs.terminal") : t("tree.newSession")}
+              </span>
+              <span className="ml-auto shrink-0 text-[11px] text-fg-muted">
+                {r.startedAt ? timeAgo(r.startedAt) : null}
+              </span>
               {r.tool === "shell" ? (
-                <>
-                  <span className="truncate">{t("tabs.terminal")}</span>
-                  <SquareTerminal aria-hidden className="ml-auto h-3.5 w-3.5 shrink-0 opacity-70" />
-                </>
+                <SquareTerminal aria-hidden className="h-3.5 w-3.5 shrink-0 opacity-70" />
               ) : (
-                <>
-                  <span className="truncate italic">{t("tree.newSession")}</span>
-                  <AiToolIcon
-                    tool={{ id: r.tool, label: tools.label(r.tool) }}
-                    className="ml-auto h-3.5 w-3.5 shrink-0 !p-0 opacity-70"
-                  />
-                </>
+                <AiToolIcon
+                  tool={{ id: r.tool, label: tools.label(r.tool) }}
+                  className="h-3.5 w-3.5 shrink-0 !p-0 opacity-70"
+                />
               )}
             </button>
           </li>
@@ -554,9 +564,12 @@ export function WorkspaceSessionList({
                     className="h-3 w-3 shrink-0 text-fg-muted"
                   />
                 )}
+                <span className="ml-auto shrink-0 text-[11px] text-fg-muted">
+                  {timeAgo(s.last_activity ?? s.started_at)}
+                </span>
                 <AiToolIcon
                   tool={{ id: s.tool || "claude", label: tools.label(s.tool || "claude") }}
-                  className="ml-auto h-3.5 w-3.5 shrink-0 !p-0 opacity-70 group-hover:invisible"
+                  className="h-3.5 w-3.5 shrink-0 !p-0 opacity-70 group-hover:invisible"
                 />
               </button>
               <button
@@ -575,11 +588,12 @@ export function WorkspaceSessionList({
           );
         })}
         {closed.map((r) => (
-          <li key={r.id}>
+          <li key={r.id} className="group relative">
             <button
               type="button"
               data-testid={`workspace-terminal-closed-${r.id}`}
               onClick={(e) => void reopenShell(e.ctrlKey || e.metaKey)}
+              onContextMenu={(e) => closedCtx.open(e, r)}
               title={t("tree.closedTerminal")}
               className="flex w-full items-center gap-2 rounded-md py-1 pl-7 pr-2 text-left text-[12px] text-fg-muted hover:bg-surface-3 hover:text-fg-primary"
             >
@@ -592,7 +606,20 @@ export function WorkspaceSessionList({
               <span className="ml-auto shrink-0 text-[11px]">
                 {timeAgo(r.ended_at ?? r.started_at)}
               </span>
-              <SquareTerminal aria-hidden className="h-3.5 w-3.5 shrink-0 opacity-70" />
+              <SquareTerminal
+                aria-hidden
+                className="h-3.5 w-3.5 shrink-0 opacity-70 group-hover:invisible"
+              />
+            </button>
+            <button
+              type="button"
+              data-testid={`workspace-terminal-forget-${r.id}`}
+              onClick={() => void forgetShell(r)}
+              title={t("tree.forgetTerminal")}
+              aria-label={t("tree.forgetTerminal")}
+              className="absolute right-1 top-1/2 -translate-y-1/2 rounded p-0.5 text-fg-muted opacity-0 hover:bg-surface-4 hover:text-fg-primary focus:opacity-100 group-hover:opacity-100"
+            >
+              <X className="h-3.5 w-3.5" />
             </button>
           </li>
         ))}
@@ -619,6 +646,42 @@ export function WorkspaceSessionList({
           onClose={ctx.close}
         />
       )}
+      {closedCtx.menu && (
+        <ContextMenu
+          x={closedCtx.menu.x}
+          y={closedCtx.menu.y}
+          onClose={closedCtx.close}
+          testId={`terminal-menu-${closedCtx.menu.item.id}`}
+        >
+          <MenuItem
+            onSelect={() => {
+              closedCtx.close();
+              void reopenShell(false);
+            }}
+          >
+            {t("tree.reopenTerminal")}
+          </MenuItem>
+          <MenuItem
+            onSelect={() => {
+              closedCtx.close();
+              void reopenShell(true);
+            }}
+          >
+            {t("sessionMenu.openSplit")}
+          </MenuItem>
+          <MenuSeparator />
+          <MenuItem
+            danger
+            onSelect={() => {
+              const item = closedCtx.menu!.item;
+              closedCtx.close();
+              void forgetShell(item);
+            }}
+          >
+            {t("tree.forgetTerminal")}
+          </MenuItem>
+        </ContextMenu>
+      )}
       {sessionCtx.menu && (
         <SessionMenu
           x={sessionCtx.menu.x}