fix: bridge port is 4403, not 4003 (v0.1.1)

meshtastic-serial-bridge listens on TCP 4403; update MESH_PORT default
in mesh.service.ts, docker-compose.yml and docs.

src/mesh/mesh.service.ts

@@ -17,7 +17,7 @@ import {
 export class MeshService implements OnModuleInit, OnModuleDestroy {
   private readonly logger = new Logger(MeshService.name);
   private readonly host = process.env.MESH_HOST ?? '192.168.1.4';
-  private readonly port = parseInt(process.env.MESH_PORT ?? '4003', 10);
+  private readonly port = parseInt(process.env.MESH_PORT ?? '4403', 10);
   // ponytail: fixed-interval retry, no backoff — fine for single-bridge use
   private readonly reconnectMs = parseInt(
     process.env.MESH_RECONNECT_MS ?? '5000',