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.

runtime/build.gradle

@@ -33,7 +33,7 @@ android {
             buildConfigField "String", "PRE_CONFIGURED_CHAIN_DETAILS_URL", "\"https://wallet.pezkuwichain.io/chain_details\""
         }
     }
-    namespace 'io.pezkuwichain.wallet.runtime'
+    namespace 'io.novafoundation.nova.runtime'
 }
 
 dependencies {