build: vendor pinned flutter_vless Android runtime

Replace build-time pub-cache mutation with a repository-owned pinned runtime so reviewed native source is the source compiled into the app.

local_packages/flutter_vless_android-1.1.5/android/src/main/AndroidManifest.xml

@@ -0,0 +1,31 @@
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="com.github.tfox.flutter_vless">
+
+    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
+    <uses-permission android:name="android.permission.INTERNET" />
+    <uses-permission android:name="android.permission.FOREGROUND_SERVICE" />
+    <uses-permission android:name="android.permission.POST_NOTIFICATIONS" />
+    <uses-permission
+        android:name="android.permission.FOREGROUND_SERVICE_SPECIAL_USE"
+        android:minSdkVersion="34" />
+
+    <application>
+        <service
+            android:name="com.github.tfox.flutter_vless.xray.service.XrayVPNService"
+            android:enabled="true"
+            android:exported="false"
+            android:foregroundServiceType="specialUse"
+            android:permission="android.permission.BIND_VPN_SERVICE"
+            android:process=":RunSoLibXrayDaemon">
+            <property
+                android:name="android.app.PROPERTY_SPECIAL_USE_FGS_SUBTYPE"
+                android:value="vpn" />
+            <intent-filter>
+                <action android:name="android.net.VpnService" />
+            </intent-filter>
+            <meta-data
+                android:name="android.net.VpnService.SUPPORTS_ALWAYS_ON"
+                android:value="false" />
+        </service>
+    </application>
+</manifest>