fix: make LLM_BASE_URL configurable with default value in docker-compose

docker-compose.yml

@@ -23,14 +23,11 @@ services:
     environment:
       # NOTE: URLs are hardcoded to container service names so that the
       # host .env file (with localhost URLs) does NOT override them.
-      # LLM: use host.docker.internal (resolved via extra_hosts) so the
-      # container reaches the LLM running on the host machine.
-      - LLM_BASE_URL=http://host.docker.internal:8011/v1
+      - LLM_BASE_URL=${LLM_BASE_URL:-http://host.docker.internal:8011/v1}
       - LLM_MODEL=${LLM_MODEL:-llama}
       - DATABASE_URL=${DATABASE_URL:-postgresql+asyncpg://agent_alpha:agent_alpha@postgres:5432/agent_alpha}
       - VALKEY_URL=${VALKEY_URL:-redis://valkey:6379/0}
 
-
     restart: unless-stopped
     depends_on:
       postgres: