Fix shutdown handling and optimize SQLite settings

- Fix Ctrl-C shutdown by using fx.Shutdowner instead of just canceling context
- Pass context from fx lifecycle to rw.Run() for proper cancellation
- Adjust WAL settings: checkpoint at 50MB, max size 100MB
- Reduce busy timeout from 30s to 2s to fail fast on lock contention

This should fix the issue where Ctrl-C doesn't cause shutdown and improve
database responsiveness under heavy load.

internal/routewatch/cli.go

@@ -58,26 +58,25 @@ func CLIEntry() {
 	app := fx.New(
 		getModule(),
 		fx.StopTimeout(shutdownTimeout), // Allow 60 seconds for graceful shutdown
-		fx.Invoke(func(lc fx.Lifecycle, rw *RouteWatch, logger *logger.Logger) {
+		fx.Invoke(func(lc fx.Lifecycle, rw *RouteWatch, logger *logger.Logger, shutdowner fx.Shutdowner) {
 			lc.Append(fx.Hook{
-				OnStart: func(_ context.Context) error {
+				OnStart: func(ctx context.Context) error {
 					// Start debug stats logging
 					go logDebugStats(logger)
 
+					// Handle shutdown signals
+					sigCh := make(chan os.Signal, 1)
+					signal.Notify(sigCh, os.Interrupt, syscall.SIGTERM)
+
 					go func() {
-						ctx, cancel := context.WithCancel(context.Background())
-						defer cancel()
-
-						// Handle shutdown signals
-						sigCh := make(chan os.Signal, 1)
-						signal.Notify(sigCh, os.Interrupt, syscall.SIGTERM)
-
-						go func() {
-							<-sigCh
-							logger.Info("Received shutdown signal")
-							cancel()
-						}()
+						<-sigCh
+						logger.Info("Received shutdown signal")
+						if err := shutdowner.Shutdown(); err != nil {
+							logger.Error("Failed to shutdown gracefully", "error", err)
+						}
+					}()
 
+					go func() {
 						if err := rw.Run(ctx); err != nil {
 							logger.Error("RouteWatch error", "error", err)
 						}