Add optional ts_code filter to GET /api/v1/cache

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app.py

@@ -297,13 +297,18 @@ async def get_predict_result(task_id: str):
 
 
 @app.get("/api/v1/cache", summary="查看缓存状态")
-async def get_cache():
+async def get_cache(ts_code: str | None = None):
     """
-    列出当前所有有效的缓存条目及其过期时间。
+    列出有效的缓存条目及其过期时间。
+
+    - 不传参数：返回全部
+    - `?ts_code=000063.SZ`：只返回该股票的所有参数组合
     """
     now_utc = datetime.now(timezone.utc)
     entries = []
     for key, entry in _cache.items():
+        if ts_code and key[0] != ts_code:
+            continue
         remaining = (entry["expires_at"] - now_utc).total_seconds()
         if remaining > 0:
             entries.append({