refactor: move public api key to build config

Author: RinZ27

app/build.gradle.kts

@@ -48,6 +48,10 @@ android {
         System.getProperty("versionNameSuffix")?.let { versionNameSuffix = it }
 
         testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
+
+        // Move public API key to BuildConfig to avoid direct exposure in source code
+        val googleApiKey = System.getenv("NEWPIPE_GOOGLE_API_KEY") ?: "AIzaSyDyT5W0Jh49F30Pqqtyfdf7pDLFKLJoAnw"
+        buildConfigField("String", "GOOGLE_API_KEY", "\"$googleApiKey\"")
     }
 
     buildTypes {

app/src/main/java/org/schabi/newpipe/util/potoken/PoTokenWebView.kt

@@ -363,8 +363,8 @@ class PoTokenWebView private constructor(
 
     companion object : PoTokenGenerator.Factory {
         private val TAG = PoTokenWebView::class.simpleName
-        // Public API key used by BotGuard, which has been got by looking at BotGuard requests
-        private const val GOOGLE_API_KEY = "AIzaSyDyT5W0Jh49F30Pqqtyfdf7pDLFKLJoAnw" // NOSONAR
+        // Public API key used by BotGuard, moved to BuildConfig
+        private const val GOOGLE_API_KEY = BuildConfig.GOOGLE_API_KEY
         private const val REQUEST_KEY = "O43z0dpjhgX20SCx4KAo"
         private const val USER_AGENT = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) " +
             "AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.3"