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).

server/routes/sessions.js

@@ -130,6 +130,13 @@ router.get("/", (req, res) => {
   // Which CLI's sessions (claude / codex / antigravity). Applied here, before
   // the limit, so a busy Codex lane cannot push Claude rows out of a page.
   const tool = typeof req.query.tool === "string" ? req.query.tool : "";
+  // `lane` = the sessions a workspace owns (`sessions.lane_id`).
+  const lane = req.query.lane;
+  if (lane !== undefined && !/^\d+$/.test(String(lane))) {
+    return res
+      .status(400)
+      .json({ error: { code: "INVALID_INPUT", message: "lane must be a lane id" } });
+  }
   const sortBy = req.query.sort_by || "time"; // "time", "duration", "price"
   const sortDesc = req.query.sort_desc !== "false";
 
@@ -153,6 +160,13 @@ router.get("/", (req, res) => {
     where.push("s.tool = ?");
     params.push(tool);
   }
+  if (lane !== undefined) {
+    where.push("s.lane_id = ?");
+    params.push(Number(lane));
+  }
+  // `archived=0|1` = only live / only archived; absent = both, as before.
+  if (req.query.archived === "0") where.push("s.archived_at IS NULL");
+  if (req.query.archived === "1") where.push("s.archived_at IS NOT NULL");
   // Data-scope filter: restrict to sessions collected from a chosen set of
   // machines (local + any configured remote sources). Absent = all sources.
   const sourceFilter = sourceColumnClause(parseSources(req));
@@ -397,6 +411,16 @@ router.patch("/:id", (req, res) => {
   if (!existing) {
     return res.status(404).json({ error: { code: "NOT_FOUND", message: "Session not found" } });
   }
+  if (Object.hasOwn(req.body, "archived")) {
+    if (typeof req.body.archived !== "boolean") {
+      return res
+        .status(400)
+        .json({ error: { code: "INVALID_INPUT", message: "archived must be a boolean" } });
+    }
+    db.prepare(
+      "UPDATE sessions SET archived_at = CASE WHEN ? THEN COALESCE(archived_at, strftime('%Y-%m-%dT%H:%M:%fZ', 'now')) END WHERE id = ?"
+    ).run(req.body.archived ? 1 : 0, req.params.id);
+  }
 
   stmts.updateSession.run(
     name || null,