fix: harden mirrored downloads and first-run upgrades

config/downloads.json

@@ -7,7 +7,11 @@
     "npm_registry": "https://registry.npmmirror.com",
     "node_mirror": "https://registry.npmmirror.com/-/binary/node",
     "adb_url": "https://mirrors.cloud.tencent.com/AndroidSDK/platform-tools-latest-windows.zip",
-    "scrcpy_url": "https://mirrors.sdu.edu.cn/github-release/Genymobile_scrcpy/v4.1/scrcpy-win64-v4.1.zip"
+    "scrcpy_url": "https://ghfast.top/https://github.com/Genymobile/scrcpy/releases/download/v4.1/scrcpy-win64-v4.1.zip",
+    "scrcpy_fallback_urls": [
+      "https://gh-proxy.com/https://github.com/Genymobile/scrcpy/releases/download/v4.1/scrcpy-win64-v4.1.zip",
+      "https://downloads.sourceforge.net/project/scrcpy.mirror/v4.1/scrcpy-win64-v4.1.zip"
+    ]
   },
   "overrides": {
     "python_index": "",
@@ -16,6 +20,7 @@
     "node_mirror": "",
     "adb_url": "",
     "scrcpy_url": "",
+    "scrcpy_fallback_urls": null,
     "uv_installer_url": ""
   }
 }