docs: archive DASHBOARD_PLAN.md and update task tracking

- Move completed DASHBOARD_PLAN.md to docs/archive/
- Update COMPLETED.md with dashboard implementation details
- Update TODO.md to reflect dashboard completion
- Mark remaining dashboard features as optional Phase 4

docs/TODO.md

@@ -362,14 +362,19 @@ See the complete security audit report generated by nodejs-security-auditor agen
 
 ### 📋 FUTURE UX/UI IMPROVEMENTS
 
-**Dashboard Page (Post-Login):**
-- [ ] Create `/dashboard` route as default landing page after login
-- [ ] Show current user information (profile summary, stats)
-- [ ] Quick access buttons to active chats (event rooms, match chats)
-- [ ] Display ongoing discussions/conversations
-- [ ] Show upcoming events user is registered for
-- [ ] Recent activity feed (new matches, messages, ratings)
-- [ ] Navigation shortcuts to key features
+**Dashboard Page - ✅ CORE COMPLETED (2025-11-21):**
+- [x] ✅ `/dashboard` route as default landing page after login
+- [x] ✅ Active events with quick access to chats
+- [x] ✅ Active matches with video/rating status
+- [x] ✅ Match requests (incoming/outgoing)
+- [x] ✅ Online count per event (real-time)
+- [x] ✅ Unread count per match
+- [x] ✅ Toast notifications for match events
+- [x] ✅ Loading skeletons
+- [x] ✅ Rate Partner button
+- [ ] ⏳ Activity Feed (timeline of all user activities) - Optional Phase 4
+- [ ] ⏳ User statistics (total matches, average rating, events attended) - Optional Phase 4
+- [ ] ⏳ Smart sort order (unread first, pending ratings, recent) - Optional Phase 4
 
 **Event Chat Sidebar Enhancements:**
 - [ ] Add competitor number display for each user in sidebar
@@ -417,6 +422,13 @@ See the complete security audit report generated by nodejs-security-auditor agen
   - Profile links from chat/matches
   - Message history persistence
   - Duplicate rating prevention
+- **Dashboard Implementation (2025-11-21)**
+  - Centralized dashboard as default landing page
+  - Active events with heats, participants, online count
+  - Active matches with video/rating status, unread count
+  - Match requests (incoming/outgoing) management
+  - Toast notifications, loading skeletons
+  - Socket stability improvements (heartbeat, auto-reconnect)
 
 **See:** `docs/archive/COMPLETED.md` for full list of completed tasks
 
@@ -880,4 +892,4 @@ git commit -m "feat: description"
 
 ---
 
-**Last Updated:** 2025-11-20
+**Last Updated:** 2025-11-21