- Added GetStats method to ChatService with database access
- Returns active_users (distinct users who sent messages in last 24h)
- Returns total_messages (non-deleted messages count)
- Returns rooms_active (rooms with messages in last 24h)
- Added GetStats handler and GET /chat/stats route
- Updated ChatService to use NewChatServiceWithDB for database access
Phase: PHASE-2
Priority: P1
Progress: 15/267 (5.6%)