fix: adb 命令超时 + STF 释放失败检查，杜绝设备卡死/占用悬空

- adb 所有命令加 30s 超时：connect 到不可达地址不再无限挂起（worker 不再卡 connecting）
- STF release 检查响应状态并重试：504 等失败不再被静默吞掉，释放失败会真实上报
- release_all_mine 返回 (released, failed)；web /api/release 透出失败列表

web_server.py

@@ -346,8 +346,8 @@ def api_stop_all():
 @app.route("/api/release", methods=["POST"])
 @login_required
 def api_release():
-    released = stf.release_all_mine()
-    return jsonify({"ok": True, "released": released})
+    released, failed = stf.release_all_mine()
+    return jsonify({"ok": True, "released": released, "failed": failed})
 
 
 @app.route("/api/device/screenshot")