feat: add emulated tool-calling bridge for Lingma

Add a proxy-side tool emulation layer so Lingma requests can surface stable OpenAI tool_calls and Anthropic tool_use blocks even when upstream tool events are missing or inconsistent.

Constraint: Keep native Lingma tool event bridging as the first path and layer emulation as a fallback

Rejected: Depend exclusively on Lingma native tool/invoke events | tool visibility remains inconsistent across models and transports

Confidence: high

Scope-risk: moderate

tests/TEST_PLAN.md

@@ -42,6 +42,7 @@
 1. 定点执行新增测试文件。
 2. 全量执行 `tests/` 下 `test_*.py`。
 3. 汇总通过率与失败项（若失败，给出定位与修复建议）。
+4. Docker 运行态执行 `bash scripts/smoke_tool_calls.sh`，验证 OpenAI / Anthropic 的 stream / non-stream 工具调用。
 
 ## 6. 执行命令
 ```bash
@@ -50,4 +51,5 @@ python3 -m unittest tests/test_session_cache_tooling.py
 python3 -m unittest tests/test_schema_normalization.py
 python3 -m unittest tests/test_tool_call_bridge.py
 python3 -m unittest discover -s tests -p "test_*.py"
+bash scripts/smoke_tool_calls.sh
 ```