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.

bindings/hydra-dx-math/build.gradle

@@ -11,7 +11,7 @@ android {
             proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
         }
     }
-    namespace 'io.pezkuwichain.wallet.hydra_dx_math'
+    namespace 'io.novafoundation.nova.hydra_dx_math'
 }
 
 dependencies {

bindings/metadata_shortener/build.gradle

@@ -1,7 +1,7 @@
 apply plugin: 'org.mozilla.rust-android-gradle.rust-android'
 
 android {
-    namespace 'io.pezkuwichain.wallet.metadata_shortener'
+    namespace 'io.novafoundation.nova.metadata_shortener'
 
     ndkVersion "26.1.10909125"