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/Assets/Editor/ChannelBuildTool.cs

@@ -33,6 +33,7 @@ public class ChannelBuildTool
         }
 
         Debug.Log($"[ChannelSwitch] Switching to {channel}...");
+        currentChannel = channel;
 
         // 1. Sync AAR
         var srcAarDir = Path.Combine(cfgDir, "Plugins/Android");
@@ -118,6 +119,8 @@ public class ChannelBuildTool
         }
     }
 
+    private static string currentChannel = "";
+
     // ==================== Menu: Switch Channel ====================
 
     [MenuItem("Tools/Switch Channel/GooglePlay")]
@@ -131,6 +134,28 @@ public class ChannelBuildTool
 
     // ==================== Menu: Build ====================
 
+    [MenuItem("Tools/Build Android (Current Channel)")]
+    public static void Build_CurrentChannel()
+    {
+        if (string.IsNullOrEmpty(currentChannel))
+        {
+            Debug.LogError("[ChannelBuild] No channel selected. Use Tools/Switch Channel first.");
+            return;
+        }
+        BuildAndroidForChannel(currentChannel, false);
+    }
+
+    [MenuItem("Tools/Build Android (Current Channel) Debug")]
+    public static void Build_CurrentChannel_Debug()
+    {
+        if (string.IsNullOrEmpty(currentChannel))
+        {
+            Debug.LogError("[ChannelBuild] No channel selected. Use Tools/Switch Channel first.");
+            return;
+        }
+        BuildAndroidForChannel(currentChannel, true);
+    }
+
     [MenuItem("Tools/Build Android (Channel)/GooglePlay")]
     public static void Build_GooglePlay() => BuildAndroidForChannel("GooglePlay", false);