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

server/__tests__/dashboard-runs.test.js

@@ -52,6 +52,15 @@ describe("dashboard-runs", () => {
     assert.equal(runs.listRuns({ laneId: 8 }).length, 2);
   });
 
+  it("forgets a closed Terminal tab and nothing of another tool", () => {
+    start("agenthub-lane-9", { laneId: 9, tool: "claude" });
+    start("agenthub-lane-9-1", { laneId: 9, tool: "shell" });
+    assert.equal(runs.forgetShellRun("agenthub-lane-9"), false);
+    assert.ok(runs.getRun("agenthub-lane-9"));
+    assert.equal(runs.forgetShellRun("agenthub-lane-9-1"), true);
+    assert.equal(runs.getRun("agenthub-lane-9-1"), null);
+  });
+
   it("flags as abandoned only the running rows whose pane is gone", () => {
     start("agenthub-lane-5", { laneId: 5 });
     start("agenthub-lane-6", { laneId: 6 });