feat(health): /health 端点添加关键模块导入自检 (#244)

特别添加了 runtime_config_support 和 runtime_execution_policy 的导入检查，
这两个模块是本次三个服务全部挂掉的直接原因。

Co-authored-by: Claude <noreply@anthropic.com>

Author: Pigbibi

main.py

@@ -4,6 +4,7 @@
 Runs on Cloud Run; token from Secret Manager, orders via LongPort OpenAPI, alerts via Telegram.
 """
 import json
+import importlib
 import os
 import time
 import traceback
@@ -846,6 +847,20 @@ def request_method() -> str:
 
 @app.route("/health", methods=["GET"])
 def health():
+    critical_errors: list[str] = []
+    for module_path in (
+        "application.runtime_composer",
+        "application.runtime_reporting_adapters",
+        "application.runtime_strategy_adapters",
+        "runtime_config_support",
+        "runtime_execution_policy",
+    ):
+        try:
+            importlib.import_module(module_path)
+        except Exception as exc:
+            critical_errors.append(f"{module_path}: {type(exc).__name__}: {exc}")
+    if critical_errors:
+        return json.dumps({"status": "unhealthy", "errors": critical_errors}, ensure_ascii=False), 500
     return "OK", 200