chore(docker): update compose files for new LLM data volume

Replace config-overrides.json mount with assistant_data volume; remove OPENAI_* env vars from e2e.

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-opencode)

docker-compose.e2e.yml

@@ -46,9 +46,6 @@ services:
       - NODE_ENV=production
       - GITEA_API_URL=http://gitea:3000/api/v1
       - GITEA_ACCESS_TOKEN=${E2E_GITEA_TOKEN:-placeholder}
-      - OPENAI_BASE_URL=${OPENAI_BASE_URL:-https://api.openai.com/v1}
-      - OPENAI_API_KEY=${OPENAI_API_KEY:-test_key}
-      - OPENAI_MODEL=${OPENAI_MODEL:-gpt-4o-mini}
       - FEISHU_WEBHOOK_URL=http://localhost:9999/noop
       - PORT=3000
       - WEBHOOK_SECRET=e2e-test-secret

docker-compose.yml

@@ -10,7 +10,7 @@ services:
     ports:
       - "3000:3000"
     volumes:
-      - ./config-overrides.json:/app/config-overrides.json
+      - assistant_data:/app/data
     env_file:
       - .env
     depends_on:
@@ -61,3 +61,5 @@ services:
 volumes:
   qdrant_data:
     driver: local
+  assistant_data:
+    driver: local