feat: merge rustore test UI and unify SKU format across channels

- Merge VK login/link/check and Review test buttons from dev_rustore
- Unify Rustore/GooglePlay SKU format via ChannelHelpers.normalizeSkuList()
- Fix ChannelConfig runtime sync: Java InitSDK sets channel from ChannelHelpers.CHANNEL
- Fix AndroidMinSdkVersion 25→26 for tuyoosdk compatibility
- Fix Flexion AndroidManifest tools:replace missing fullBackupContent value
- Add [CHANNEL-VERIFY] debug logs for channel verification

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

sdk-intergration/Packages/tysdk/Plugins/Android/SDKManager.java

@@ -77,13 +77,16 @@ public class SDKManager {
     // -------------------------------------------------------------------------
 
     public static void InitSDK(Activity activity, String ch) {
-        channel = ch != null ? ch : "GooglePlay";
+        channel = ChannelHelpers.CHANNEL;
         ChannelHelpers.register();
-        if (!channel.equals(ChannelHelpers.CHANNEL)) {
-            Log.e(TAG, "Channel mismatch! Helpers=" + ChannelHelpers.CHANNEL + " expected=" + channel);
-        }
         sdkHelper = helperMap.get(channel);
-        Log.i(TAG, "InitSDK channel=" + channel + " helper=" + (sdkHelper != null ? sdkHelper.getClass().getSimpleName() : "none"));
+        Log.i(TAG, "[CHANNEL-VERIFY] Java InitSDK channel=" + channel
+                + " fromCSharp=" + ch
+                + " helper=" + (sdkHelper != null ? sdkHelper.getClass().getSimpleName() : "default"));
+
+        // Sync channel to C# ChannelConfig
+        UnityPlayer.UnitySendMessage(ConfigManager.UNITY_FACADE_NAME,
+                "SetChannelFromNative", channel);
 
         if (sdkHelper != null) {
             sdkHelper.init(activity);
@@ -422,7 +425,7 @@ public class SDKManager {
                     JSONObject result = new JSONObject();
                     result.put("code", code);
                     if (code == SDKCallBack.Extend.EXTEND_CODE_SUCCESS) {
-                        result.put("respObj", msg);
+                        result.put("respObj", ChannelHelpers.normalizeSkuList(msg));
                     } else {
                         Log.e(TAG, "thirdExtend failed: " + msg);
                         result.put("thirdExtend_errStr", msg);