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/WebhookSettings.tsx

@@ -58,6 +58,7 @@
  *
  * ----------------------------------------------------------------------------- */
 
+import { Switch } from "./Switch";
 import { useCallback, useEffect, useMemo, useState } from "react";
 import { useTranslation } from "react-i18next";
 import {
@@ -132,34 +133,6 @@ function defaultsFor(provider: WebhookProvider | undefined): Record<string, stri
   return out;
 }
 
-function Toggle({
-  checked,
-  onChange,
-  label,
-}: {
-  checked: boolean;
-  onChange: (v: boolean) => void;
-  label?: string;
-}) {
-  return (
-    <button
-      type="button"
-      role="switch"
-      aria-checked={checked}
-      aria-label={label}
-      onClick={() => onChange(!checked)}
-      className={`relative inline-flex h-5 w-9 flex-shrink-0 items-center rounded-full transition-colors ${
-        checked ? "bg-blue-600" : "bg-surface-4"
-      }`}
-    >
-      <span
-        className="inline-block h-3.5 w-3.5 rounded-full bg-white transition-transform"
-        style={{ transform: checked ? "translateX(18px)" : "translateX(3px)" }}
-      />
-    </button>
-  );
-}
-
 export function WebhookSettings() {
   const { t } = useTranslation("settings");
   const [targets, setTargets] = useState<WebhookTarget[]>([]);
@@ -452,7 +425,7 @@ export function WebhookSettings() {
                         {timeAgo(target.last_delivery.created_at)}
                       </span>
                     )}
-                    <Toggle
+                    <Switch
                       checked={target.enabled}
                       onChange={() => onToggle(target)}
                       label={t("webhooks.enabled")}
@@ -772,7 +745,7 @@ export function WebhookSettings() {
 
           <div className="flex items-center gap-3 pt-1">
             <label className="inline-flex items-center gap-2 text-[11px] text-fg-secondary cursor-pointer">
-              <Toggle checked={form.enabled} onChange={(v) => set({ enabled: v })} />
+              <Switch checked={form.enabled} onChange={(v) => set({ enabled: v })} />
               {t("webhooks.enabledOnSave")}
             </label>
           </div>