feat(meetings): live invite, scheduling calendar, Discord-style redesign

- Live invite: ring a clinic member into a room (socket call:invite + a bell
  notification); the invitee gets a toast with a Join action. Notifications of
  type "meeting" deep-link to /messages/meetings?room=, which auto-joins.
- Scheduling: new scheduled_meetings table + /api/meetings/events (list mine,
  create, delete); a Calendar tab on the Meetings page with a month picker
  (meeting-day dots), the day's agenda, and a Schedule-meeting dialog
  (title/date/time/participants).
- Redesign: rounded control bar with tooltips (mic/cam/screen/invite + separated
  red Leave), speaking ring on tiles (Web Audio), and live room-occupancy counts
  via call:presence broadcasts. Migration 0025.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/lib/notifications.ts

@@ -39,6 +39,8 @@ export function notificationHref(n: Notification): string | null {
   switch (n.entityType) {
     case "conversation":
       return `/messages?conversation=${encodeURIComponent(n.entityId)}`;
+    case "meeting":
+      return `/messages/meetings?room=${encodeURIComponent(n.entityId)}`;
     case "patient":
       return `/patients?file=${encodeURIComponent(n.entityId)}`;
     default: