Add notification bell, settings modal, and context-sensitive footer

- Notification bell in header polls /api/status and shows active alerts
  with severity-colored dots; badge counts unread items via localStorage
- Settings modal ([ * ] CFG) controls auto-refresh interval (15s/30s/1m/5m/off)
  persisted to localStorage and wired into lt.autoRefresh on all pages
- Context-sensitive footer hints: Dashboard shows REFRESH + SUPPRESS,
  Link Debug shows REFRESH, all pages show CFG + HELP
- Added S key (quick suppress) and * key (settings) shortcuts
- ⌘K affordance button added to header-right
- R key now uses lt.autoRefresh.now() so it works on any page
- refreshAll() pushes fresh events to notification bell on each poll

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

static/app.js

@@ -53,6 +53,7 @@ async function refreshAll() {
       const status = statusResult.value;
       updateEventsTable(status.events || [], status.total_active);
       updateStatusBar(status.summary || {}, status.last_check || '', status.daemon_ok);
+      if (typeof window.gandalfNotifUpdate === 'function') window.gandalfNotifUpdate(status.events || []);
     } else {
       showToast('Status data unavailable', 'warning');
     }