fix: revert gradle namespaces, add release Firebase config

Reverted gradle namespace changes (io.pezkuwichain.wallet -> io.novafoundation.nova)
because they break R class references in Kotlin code.

Internal namespaces are NOT user-visible, so this is acceptable for minimum rebrand.
User-visible elements are all properly branded as Pezkuwi.

Added google-services.json for release variant.

feature-settings-impl/build.gradle

@@ -2,7 +2,7 @@ apply plugin: 'kotlin-parcelize'
 apply from: '../tests.gradle'
 
 android {
-    namespace 'io.pezkuwichain.wallet.feature_settings_impl'
+    namespace 'io.novafoundation.nova.feature_settings_impl'
 
     buildTypes {
         release {