ci: correctly declare local network

docker-compose.yml

@@ -34,9 +34,8 @@ services:
     networks:
       - bot-net
 
-volumes:
-  postgres_data:
-
 networks:
   bot-net:
-    external: true
+
+volumes:
+  postgres_data:

docs/infra.md

@@ -120,6 +120,8 @@ jobs:
 
 Alternatively, deploy the repository as a Dokploy Compose service using
 `docker-compose.yml`. This runs both the bot and PostgreSQL in one stack.
+Compose creates the `bot-net` network itself; it must not be declared
+`external` unless it is created separately in advance.
 
 Check logs in Dokploy after deploy. A successful start shows the bot polling
 Telegram with no errors. If the process exits, the most common causes are a