feat: feature requests board with voting

- [FEATURES] tab next to PINNED in channel header
- Create, vote/unvote, filter by status (open/planned/done/rejected)
- Sort by vote count (most voted first)
- Status selector for moderation
- DB: feature_requests + feature_request_votes tables
- Backend: full CRUD + vote endpoints under /servers/{id}/feature-requests

cmd/server/main.go

@@ -232,6 +232,12 @@ func main() {
 				pollHandler.RegisterRoutes(r)
 			})
 
+			// Feature requests
+			frHandler := message.NewFeatureRequestHandler(database.DB)
+			r.Route("/servers/{serverID}/feature-requests", func(r chi.Router) {
+				frHandler.RegisterRoutes(r)
+			})
+
 			// Per-channel notification settings
 			r.Route("/channels/{channelID}/notifications", func(r chi.Router) {
 				notification.NewHandler(database.DB, logger).RegisterRoutes(r)