refactor: remove duplicate Server methods and clean up main.go

- Removed all duplicate Server methods from main.go (630 lines)
- Fixed import conflicts and unused imports
- main.go reduced from 3,298 to 340 lines (89% reduction)
- Clean modular structure with server package handling all server functionality
- Achieved clean build with no compilation errors

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

server/routes.go

@@ -51,4 +51,4 @@ func (s *Server) setupRoutes() *mux.Router {
 	router.HandleFunc("/api/backup/status", s.getBackupStatusHandler).Methods("GET")
 
 	return router
-}
+}