Rename handlers and add PrefixHandler for database routing table

- Renamed BatchedDatabaseHandler to DBHandler
- Renamed BatchedPeerHandler to PeerHandler
- Quadrupled DBHandler batch size from 4000 to 16000
- Created new PrefixHandler using same batching strategy to maintain routing table in database
- Removed verbose batch flush logging from all handlers
- Updated app.go to use renamed handlers and register PrefixHandler
- Fixed test configuration to enable batched database writes

internal/routewatch/app_integration_test.go

@@ -175,8 +175,9 @@ func TestRouteWatchLiveFeed(t *testing.T) {
 
 	// Create test config with empty state dir (no snapshot loading)
 	cfg := &config.Config{
-		StateDir:   "",
-		MaxRuntime: 5 * time.Second,
+		StateDir:                    "",
+		MaxRuntime:                  5 * time.Second,
+		EnableBatchedDatabaseWrites: true,
 	}
 
 	// Create routing table