Update README and docker-compose files

README.md

@@ -97,7 +97,9 @@ any skipped checks in work reports.
 | `NEXO_PUSH_PROXY_PORT` | Host port mapped to push-proxy `8066` | No |
 
 See `services/core/compose/.env.example` for example values. Do not commit real
-`.env` files or runtime data.
+`.env` files or runtime data. The Docker network subnet is fixed to
+`172.38.0.0/16`; reserve this range for nexo and do not reuse it for other Docker
+networks.
 
 ### Optional Verification
 

services/core/compose/README.md

@@ -16,3 +16,6 @@ testing is needed.
 
 The default host ports are `18065` for core and `18066` for push-proxy so this
 test deployment can run beside the existing Mattermost service.
+
+The Docker network subnet is fixed to `172.38.0.0/16`. Treat this range as
+reserved for nexo and do not reuse it for other Docker networks.

services/core/compose/docker-compose.yml

@@ -75,3 +75,7 @@ services:
 networks:
   net_nexo_core:
     name: net_nexo_core
+    ipam:
+      driver: default
+      config:
+        - subnet: 172.38.0.0/16