build, add flutter proguard file.

android/app/build.gradle.kts

@@ -55,7 +55,8 @@ android {
             isShrinkResources = true
             proguardFiles(
                 getDefaultProguardFile("proguard-android-optimize.txt"),
-                "proguard-rules.pro"
+                "proguard-rules.pro",
+                "flutter_proguard_rules.pro"
             )
 
             /// 20260928 - With minifying, helped some, but also used