v0.3.0-alpha - SDK wiring + native stubs (Phase 2)

Phase 2 of 10. Declares the real Google AdMob SDK dependencies, registers ADMOB_APP_ID as a required secret, ships SKAdNetwork identifiers for iOS, and adds stub native code so the manifest validates and a NativePHP build links cleanly with the SDK initialised at app boot.

What's new

• Android SDK deps:
  • com.google.android.gms:play-services-ads:25.3.0
  • com.google.android.ump:user-messaging-platform:4.0.0
• iOS SDK deps:
  • Google-Mobile-Ads-SDK ~> 13.4
  • GoogleUserMessagingPlatform ~> 2.7
• ADMOB_APP_ID secret: required at build time. Auto-injected into AndroidManifest.xml (com.google.android.gms.ads.APPLICATION_ID meta-data) and Info.plist (GADApplicationIdentifier).
• 50 SKAdNetwork identifiers shipped in iOS Info.plist SKAdNetworkItems as the iOS attribution starter set. README points to Google's canonical list for refreshing.
• NSUserTrackingUsageDescription with sensible default copy.
• Native init functions (AdmobInit.initialize) on both platforms - the Google Mobile Ads SDK is initialised at app boot via NativePHP's init_function mechanism. Honours ADMOB_TEST_DEVICES env var for test device registration.
• Stub bridge function classes for all 22 entries in the manifest. Admob.Platform returns the real platform identifier; everything else returns a "not implemented in v0.3.x" error.

Verified

• vendor/bin/pest: 49 passed (88 assertions) - no regressions from Phase 1.
• vendor/bin/pint --test: clean.
• php artisan native:plugin:validate from a consumer app: OK against this plugin's manifest.

Not yet shipped

• Real banner / interstitial / rewarded / rewarded-interstitial / app-open implementations - Phase 3.
• UMP consent form rendering, ATT prompt - Phase 4 / 5.
• JS library stub.
• Blade <x-admob::banner> component.

Do not depend on this version in production.