refactor: ota目录优化 — h5-manifest-*.json移至根+更新Bridge URL

- ota/h5/manifest-*.json → ota/h5-manifest-*.json
- MainActivity.kt: fetchManifest URL更新
- APK manifest + h5 manifest命名冲突消除

packages/client-android/android/app/src/main/java/dev/yuzu/gca/MainActivity.kt

@@ -65,7 +65,7 @@ class MainActivity : AppCompatActivity() {
         /** Fetch manifest JSON from Gitea — proxy to avoid CORS in WebView */
         @android.webkit.JavascriptInterface
         fun fetchManifest(channel: String): String {
-            val url = "https://git.childish-ghost.com/LukeMackin/Yuzu-GCA/raw/branch/main/ota/h5/manifest-$channel.json"
+            val url = "https://git.childish-ghost.com/LukeMackin/Yuzu-GCA/raw/branch/main/ota/h5-manifest-$channel.json"
             Log.i(TAG, "Bridge fetching $url")
             return try {
                 val conn = URL(url).openConnection() as HttpURLConnection