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.md

@@ -56,7 +56,6 @@ The repository uses a **split-service runtime model** for local development and
 | `backend.apps.trading_service` | `:8001` | Read-only trading data APIs |
 | `backend.apps.news_service` | `:8002` | Read-only explain/news APIs |
 | `backend.apps.runtime_service` | `:8003` | Runtime lifecycle APIs |
-| `backend.apps.openclaw_service` | `:8004` | Read-only OpenClaw facade |
 | WebSocket gateway | `:8765` | Live event/feed channel for the frontend |
 
 ### Active Runtime Path