feat: integrate real data into dashboard

- Created dashboard service with DB queries for users, economy, events
- Added client stats provider with 30s caching for Discord metrics
- Implemented /api/stats endpoint aggregating all dashboard data
- Created useDashboardStats React hook with auto-refresh
- Updated Dashboard.tsx to display real data with loading/error states
- Added comprehensive test coverage (11 tests passing)
- Replaced all mock values with live Discord and database metrics

.gitignore

@@ -44,5 +44,4 @@ report.[0-9]_.[0-9]_.[0-9]_.[0-9]_.json
 
 src/db/data
 src/db/log
-scratchpad/
-tickets/
+scratchpad/