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/lib/__tests__/panePaste.test.ts

@@ -0,0 +1,33 @@
+/**
+ * @file panePaste.test.ts
+ * @description Pins where a pasted diff comment lands: the workspace's pane
+ * focused last, else any of its panes, never another workspace's (lane 1 is
+ * not lane 12), and nowhere once the pane unmounted.
+ * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
+ */
+
+import { describe, expect, it } from "vitest";
+import { notePaneFocus, pasteToLane, registerPane } from "../panePaste";
+
+describe("panePaste", () => {
+  it("pastes into the workspace's last-focused pane, and only its own", () => {
+    const got: Record<string, string[]> = {};
+    const reg = (id: string) => registerPane(id, (t) => (got[id] ??= []).push(t));
+    const off12 = reg("agenthub-lane-12");
+    const off0 = reg("agenthub-lane-1");
+    const off2 = reg("agenthub-lane-1-2");
+    expect(pasteToLane(1, "a")).toBe(true);
+    expect(got["agenthub-lane-1"]).toEqual(["a"]);
+    notePaneFocus("agenthub-lane-1-2");
+    pasteToLane(1, "b");
+    expect(got["agenthub-lane-1-2"]).toEqual(["b"]);
+    // Focus on another workspace's pane does not pull lane 1's text there.
+    notePaneFocus("agenthub-lane-12");
+    pasteToLane(1, "c");
+    expect(got["agenthub-lane-12"]).toBeUndefined();
+    off0();
+    off2();
+    expect(pasteToLane(1, "d")).toBe(false);
+    off12();
+  });
+});