Initial commit: Pezkuwi Wallet Android

Security hardened release:
- Code obfuscation enabled (minifyEnabled=true, shrinkResources=true)
- Sensitive files excluded (google-services.json, keystores)
- Branch.io key moved to BuildConfig placeholder
- Updated dependencies: OkHttp 4.12.0, Gson 2.10.1, BouncyCastle 1.77
- Comprehensive ProGuard rules for crypto wallet
- Navigation 2.7.7, Lifecycle 2.7.0, ConstraintLayout 2.1.4

key/fake.json

@@ -0,0 +1,12 @@
+{
+  "type": "null",
+  "project_id": "null",
+  "private_key_id": "null",
+  "private_key": "-----BEGIN PRIVATE KEY-----\nnull\n-----END PRIVATE KEY-----\n",
+  "client_email": "null@null.iam.gserviceaccount.com",
+  "client_id": "null",
+  "auth_uri": "https://accounts.google.com/o/oauth2/auth",
+  "token_uri": "https://oauth2.googleapis.com/token",
+  "auth_provider_x509_cert_url": "https://www.googleapis.com/oauth2/v1/certs",
+  "client_x509_cert_url": "https://www.googleapis.com/robot/v1/metadata/x509/null.iam.gserviceaccount.com"
+}