feat: 失败任务汇总 - /api/summary + 监控页异常面板

- 新增 /api/summary：各状态计数 + 异常设备列表（last_error/任务/重试次数/时间）
- 监控页新增"异常汇总"面板：显示失败/异常设备及错误信息，方便长期运行观察健康度

web_server.py

@@ -28,6 +28,7 @@ from flask_login import (LoginManager, login_user, logout_user,
 
 from core.stf_client import STFClient
 from core.task_manager import TaskManager
+from core.device_worker import get_all_worker_status
 from core.logger import get_logger, _LOG_DIR, _MODULE_FILES
 from core.models import db, init_db, User, DeviceGroup, TaskJob, CustomAction
 from core.apk_manager import ApkManager
@@ -147,6 +148,40 @@ def api_health():
         return jsonify({"ok": False, "status": "down", "error": str(e)}), 500
 
 
+# ================== API：失败任务汇总 ==================
+@app.route("/api/summary")
+@login_required
+def api_summary():
+    """失败/异常任务汇总：各状态计数 + 异常设备列表（last_error / 重试次数）。
+
+    供监控页"异常汇总"面板使用，便于长期运行观察设备健康度。
+    """
+    try:
+        sts = get_all_worker_status()
+        counts = {"total": 0, "running": 0, "done": 0,
+                  "error": 0, "failed": 0, "idle": 0}
+        errors = []
+        for s in sts:
+            st = s.get("status", "idle")
+            counts["total"] += 1
+            if st in counts:
+                counts[st] += 1
+            if st in ("error", "failed") and s.get("last_error"):
+                errors.append({
+                    "serial": s.get("serial"),
+                    "model": s.get("model", ""),
+                    "status": st,
+                    "last_error": s.get("last_error", ""),
+                    "task": s.get("task_job", ""),
+                    "attempt": s.get("attempt", 0),
+                    "updated": s.get("last_heartbeat", 0),
+                })
+        errors.sort(key=lambda x: x.get("updated", 0), reverse=True)
+        return jsonify({"ok": True, "counts": counts, "errors": errors[:50]})
+    except Exception as e:
+        return jsonify({"ok": False, "error": str(e)}), 500
+
+
 # ================== API：状态（监控大屏用）==================
 @app.route("/api/status")
 @login_required