Add ThunderID official Kotlin based native Android SDK

[brionmario]

Purpose

Introduces the official ThunderID Kotlin-based native Android SDK. This is the initial implementation of the SDK in its own dedicated repository (thunder-id/android-sdks), covering the core client, authentication (PKCE), token management, Compose UI components, and a quickstart sample app.

Approach

Structured the SDK as a Gradle multi-module project with two main layers:

• Core (dev.thunderid.android) — ThunderIDClient, ThunderIDConfig, PKCE-based auth flow (FlowExecutionClient, PKCEManager), token lifecycle (TokenStore, TokenValidator, TokenRefresher, JWKSCache), an HTTP client, and a StorageAdapter abstraction.
• Compose (dev.thunderid.compose) — ThunderIDProvider, ThunderIDState, LocalThunderID, and prebuilt components (SignInButton, SignOutButton, and others) for drop-in integration.

Also includes a samples/quickstart app (AuthScreen, HomeScreen, MainActivity, RootView) demonstrating a full sign-in/sign-out flow, along with CI via a PR builder workflow.

Related Issues

• ThunderID Android SDK thunderid#2122

Related PRs

• [Docs] Add ThunderID official Kotlin based native Android SDK Docs thunderid#3351

Checklist

• Followed the contribution guidelines.
• Manual test round performed and verified.
• Documentation provided. (Add links if there are any)
• Tests provided. (Add links if there are any)
  • Unit Tests
  • Integration Tests
• Breaking changes. (Fill if applicable)
  • Breaking changes section filled.
  • breaking change label added.

Security checks

• Followed secure coding standards in WSO2 Secure Coding Guidelines
• Confirmed that this PR doesn't commit any keys, passwords, tokens, usernames, or other secrets.