Implement components + uploads flow and gateway-aligned payloads

lib/server.dart

@@ -8,6 +8,7 @@ import 'src/handlers/auth_handlers.dart';
 import 'src/handlers/channel_handlers.dart';
 import 'src/handlers/message_handlers.dart';
 import 'src/handlers/public_handlers.dart';
+import 'src/handlers/upload_handlers.dart';
 import 'src/state/app_state.dart';
 
 RelicApp? _currentApp;
@@ -27,6 +28,7 @@ Future<void> startServer() async {
     ..get('/.well-known/users/:username', publicUserHandler)
     ..get('/.well-known/verify/:userId', publicVerifyHandler)
     ..get('/.well-known/server', publicServerInfoHandler)
+    ..get('/uploads/:fileName', getUploadFileHandler)
     ..get('/gateway', gatewayHandler)
 
     // ============ PROTECTED ENDPOINTS (requires auth) ============
@@ -42,6 +44,7 @@ Future<void> startServer() async {
 
     // Messages
     ..get('/api/messages', getMessagesHandler)
+    ..post('/api/uploads', uploadFileHandler)
     ..post('/api/messages', sendMessageHandler)
     ..put('/api/messages/:messageId', editMessageHandler)
     ..delete('/api/messages/:messageId', deleteMessageHandler)