fix(recommendations): 优化推荐服务进程检查逻辑

更新 `_recommendations_process_running` 函数，增强对推荐服务进程的检查能力，支持 pgrep 和 ps 方式，确保在不同环境下均能准确获取进程状态。此改动提升了系统的稳定性与兼容性，确保推荐服务的有效管理。

backend/api/routes/system.py

@@ -1355,18 +1355,35 @@ async def backend_stop(_admin: Dict[str, Any] = Depends(require_system_admin)) -
 
 
 def _recommendations_process_running() -> Tuple[bool, Optional[int]]:
-    """检查推荐服务进程是否运行，返回 (running, pid)"""
+    """检查推荐服务进程是否运行，返回 (running, pid)。兼容 pgrep/ps 及 supervisor 等启动方式。"""
+    # 1. 优先 pgrep（Linux/macOS 常见）
+    for pattern in ["trading_system.recommendations_main", "recommendations_main"]:
+        try:
+            result = subprocess.run(
+                ["pgrep", "-f", pattern],
+                capture_output=True,
+                text=True,
+                timeout=5,
+            )
+            if result.returncode == 0 and result.stdout.strip():
+                pids = [x for x in result.stdout.strip().split() if x.isdigit()]
+                if pids:
+                    return True, int(pids[0])
+        except (FileNotFoundError, subprocess.TimeoutExpired, ValueError):
+            break
+
+    # 2. 回退：ps + grep（pgrep 不可用或匹配失败时）
     try:
         result = subprocess.run(
-            ["pgrep", "-f", "trading_system.recommendations_main"],
+            ["sh", "-c", "ps aux 2>/dev/null | grep -E 'recommendations_main|trading_system.recommendations' | grep -v grep | head -1"],
             capture_output=True,
             text=True,
             timeout=5,
         )
         if result.returncode == 0 and result.stdout.strip():
-            pids = result.stdout.strip().split()
-            pid = int(pids[0]) if pids else None
-            return True, pid
+            parts = result.stdout.strip().split()
+            if len(parts) >= 2 and parts[1].isdigit():
+                return True, int(parts[1])
     except (FileNotFoundError, subprocess.TimeoutExpired, ValueError):
         pass
     return False, None