Add production hardening: health check, streamer panic fix, db maintenance

- Add health check endpoint at /.well-known/healthcheck.json that
  verifies database and RIS Live connectivity, returns 200/503

- Fix panic in streamer when encountering unknown RIS message types
  by logging a warning and continuing instead of crashing

- Add DBMaintainer for periodic database maintenance:
  - VACUUM every 6 hours to reclaim space
  - ANALYZE every hour to update query statistics
  - Graceful shutdown support

- Add Vacuum() and Analyze() methods to database interface

internal/routewatch/app_integration_test.go

@@ -405,6 +405,16 @@ func (m *mockStore) UpdatePeerBatch(peers map[string]database.PeerUpdate) error
 	return nil
 }
 
+// Vacuum mock implementation
+func (m *mockStore) Vacuum(ctx context.Context) error {
+	return nil
+}
+
+// Analyze mock implementation
+func (m *mockStore) Analyze(ctx context.Context) error {
+	return nil
+}
+
 func TestRouteWatchLiveFeed(t *testing.T) {
 
 	// Create mock database