fix(memos-local-plugin): start stdio before host LLM fallback

[hijzy]

Summary

• start the Hermes stdio bridge before core.init() so startup recovery can use host LLM fallback safely
• clean up stdio/heartbeat if core init fails
• make the Hermes Python bridge client wait briefly for late reverse-RPC host handler registration
• add regression coverage for delayed host.llm.complete handler registration

Tests

• /Users/jiang/MyProject/MemOS-jiang/.venv/bin/ruff format adapters/hermes/memos_provider/bridge_client.py tests/python/test_bridge_client.py
• /Users/jiang/MyProject/MemOS-jiang/.venv/bin/ruff check adapters/hermes/memos_provider/bridge_client.py tests/python/test_bridge_client.py
• npm run lint
• npm test -- tests/unit/bridge/stdio.test.ts tests/unit/llm/client.test.ts
• python3 -m unittest tests.python.test_bridge_client.BridgeClientTests