[Feature] Add AdMob Ads SDK integration skill

### Proposed Skill
Requesting a new skill to guide developers through integrating and managing the **Google Mobile Ads (AdMob) SDK** in Android applications using modern Android development practices (Kotlin, Jetpack Compose / View-based layouts).

### Additional Context
The skill should provide guidance, boilerplate code, and review capabilities for:

1. **SDK Setup & Configuration**
- Adding `play-services-ads` dependency and initializing the SDK properly (`MobileAds.initialize`).
- Configuring `AndroidManifest.xml` with the AdMob App ID (`com.google.android.gms.ads.APPLICATION_ID`).

2. **Ad Format Implementations (Jetpack Compose & Views)**
- **Banner Ads:** Composables (`AndroidView` wrapped `AdView`) and XML layout integration.
- **Interstitial Ads:** Preloading, show/dismiss callbacks, and lifecycle awareness.
- **Rewarded Ads & Rewarded Interstitial:** Granting rewards via callbacks securely.
- **Native Ads:** Custom layout binding and asset handling.

Start by reviewing how existing skills in the repository are structured, then map the requested AdMob setup to play-services-ads, MobileAds.initialize, and AndroidManifest.xml. Cover the listed banner, interstitial, rewarded, rewarded interstitial, and native formats for Compose and Views, with lifecycle and secure reward guidance; done means the skill provides guidance, boilerplate, and review coverage for each requested area.

Written by the indexing model from the issue text.