docs: remove references to deleted OpenClaw REST facade (port 8004)

Update all documentation to reflect removal of OpenClaw REST service:
- README.md, README_zh.md: remove service table entry
- deploy/README.md: update port range 8000-8003
- services/README.md: remove 8004 references and service list
- docs/compat-removal-plan.md: remove REST surface mention
- docs/current-architecture.md: remove service reference
- docs/legacy-inventory.md: simplify to WebSocket-only description

Follow-up to: refactor(openclaw): remove REST facade

README_zh.md

@@ -54,7 +54,6 @@
 | `backend.apps.trading_service` | `:8001` | 只读交易数据 API |
 | `backend.apps.news_service` | `:8002` | 只读 explain/news API |
 | `backend.apps.runtime_service` | `:8003` | 运行时生命周期 API |
-| `backend.apps.openclaw_service` | `:8004` | 只读 OpenClaw facade |
 | WebSocket gateway | `:8765` | 前端实时事件/feed 通道 |
 
 ### 活跃运行时路径