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/panePaste.ts

@@ -0,0 +1,42 @@
+/**
+ * @file panePaste.ts — lets another part of the Workspace page paste text into
+ * a workspace's terminal (a diff-line comment from the Changes panel). Every
+ * mounted TerminalView registers its run id; the text goes to the pane of that
+ * workspace the user focused last, else any of its panes. It is a paste —
+ * bracketed, so `claude` takes it as one block in its composer — and never an
+ * Enter: the user reads it and sends it.
+ * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
+ */
+
+const panes = new Map<string, (text: string) => void>();
+let lastFocused: string | null = null;
+
+/** Registers a mounted terminal; returns its unregister. */
+export function registerPane(runId: string, paste: (text: string) => void): () => void {
+  panes.set(runId, paste);
+  return () => {
+    if (panes.get(runId) === paste) panes.delete(runId);
+    if (lastFocused === runId) lastFocused = null;
+  };
+}
+
+export function notePaneFocus(runId: string): void {
+  lastFocused = runId;
+}
+
+/** The tmux names of workspace `laneId`'s panes: `agenthub-lane-<id>[-slot]`. */
+function ofLane(runId: string, laneId: number): boolean {
+  const base = `agenthub-lane-${laneId}`;
+  return runId === base || runId.startsWith(`${base}-`);
+}
+
+/** Pastes `text` into one of the workspace's mounted panes; false when none is. */
+export function pasteToLane(laneId: number, text: string): boolean {
+  const id =
+    lastFocused && panes.has(lastFocused) && ofLane(lastFocused, laneId)
+      ? lastFocused
+      : [...panes.keys()].find((k) => ofLane(k, laneId));
+  if (!id) return false;
+  panes.get(id)!(text);
+  return true;
+}