feat: workspaces own their sessions; desktop parity; sidebar and settings cleanup

Workspace sessions (docs/plans/desktop-parity, phases 1-5 and 7):
- sessions.lane_id: a workspace lists only the sessions its panes held,
  stamped by bindRunSession (first writer wins, nested `claude -p`
  excluded); GET /api/sessions?lane=&archived=
- session row state dot, double-click rename, archive (sessions.archived_at,
  hides only); the activity bar's duplicate Sessions tab removed
- Fork beside Resume (--fork-session, Claude only), Ctrl/Cmd+click a live
  session opens it in a second pane, a diff line's comment is pasted into
  the workspace's last-focused pane (lib/panePaste.ts)

dashboard_runs stability:
- a pane's previous run is archived as <pane>@<started_at> instead of being
  overwritten by INSERT OR REPLACE
- a run is flagged abandoned only once its tmux session is gone, at boot and
  on the run-heal beat (panes outlive a server restart)

UI:
- sidebar: no footer, language or theme block; small collapse button in the
  brand corner; version + update check in the connection details modal, a
  status-bar dot while a release is out; language in Settings -> General
- one Switch component for every switch, the themed Checkbox for every
  checkbox (no native checkboxes)

Also: AI Tools catalog trimmed to 10 built-ins (custom-file prompt modes
tested through fixtures), and the workspace plans under docs/plans/ (the
multi-user server plan lives in the AgentHub-Server repo).

client/src/components/lanes/__tests__/WorkspaceHome.test.tsx

@@ -62,7 +62,10 @@ vi.mock("../../../lib/api", async (importOriginal) => {
         routerList: vi.fn(async () => ({ routers: [] })),
       },
       run: { list: vi.fn(async () => ({ items: runs })) },
-      sessions: { list: vi.fn(async () => ({ sessions })) },
+      sessions: {
+        list: vi.fn(async () => ({ sessions })),
+        patch: vi.fn(async () => ({ session: {} })),
+      },
       projects: {
         list: vi.fn(async () => ({
           projects: [
@@ -134,6 +137,12 @@ function renderHome(l = lane()) {
 beforeEach(() => {
   localStorage.clear();
   vi.clearAllMocks();
+  vi.mocked(api.sessions.list).mockImplementation(async () => ({
+    sessions,
+    total: sessions.length,
+    limit: 30,
+    offset: 0,
+  }));
   view = {
     instructions: "",
     supported: true,
@@ -196,11 +205,28 @@ describe("WorkspaceHome", () => {
     expect(api.lanes.action).not.toHaveBeenCalled();
   });
 
+  it("folds the archived sessions with Unarchive", async () => {
+    vi.mocked(api.sessions.list).mockImplementation(async (params) => ({
+      sessions: (params as { archived?: boolean }).archived ? [sessions[1]!] : [],
+      total: (params as { archived?: boolean }).archived ? 1 : 0,
+      limit: 30,
+      offset: 0,
+    }));
+    const user = userEvent.setup();
+    renderHome();
+    const fold = await screen.findByTestId("workspace-archived-1");
+    await user.click(within(fold).getByRole("button", { name: /1 archived session/ }));
+    await user.click(within(fold).getByTestId("workspace-archived-1-action-s-old"));
+    expect(api.sessions.patch).toHaveBeenCalledWith("s-old", { archived: false });
+  });
+
   it("opens a live recent's pane and an ended one's transcript, resuming nothing", async () => {
     const user = userEvent.setup();
     renderHome();
     const live = await screen.findByTestId("workspace-recent-s-live");
     await waitFor(() => expect(live).toHaveAttribute("data-live", "true"));
+    // Recents are the workspace's OWN sessions, not the folder's.
+    expect(api.sessions.list).toHaveBeenCalledWith({ lane: 1, archived: false, limit: 30 });
     await user.click(live);
     expect(screen.getByTestId("where").textContent).toBe("/workspace?lane=1&run=agenthub-lane-1");
     await user.click(screen.getByTestId("workspace-recent-s-old"));