fix(ci): install Android cmdline-tools and accept NDK licenses properly

[assassinaj602]

Description

Fixes the CI pipeline where the Android SDK and NDK were failing to be detected or initialized on the GitHub Actions runner.

Changes Made

• Android SDK & cmdline-tools: Properly install commandlinetools, export ANDROID_HOME, and add sdkmanager to GITHUB_PATH
• SDK Licenses: Auto-accept SDK licenses using yes | sdkmanager --licenses
• NDK Installation: Install Android NDK 28.0.12433566 and export ANDROID_NDK_HOME
• CMake 3.31.0: Install CMake 3.31.0 for fllama native compatibility
• Example App SDK Versions: Set compileSdk = 34 and ndkVersion = "28.0.12433566" in example/android/app/build.gradle.kts
• local.properties: Added sdk.dir definition for example Android build

Verification

• All 10 atomic commits created and pushed to fix/ci-android-sdk
• flutter analyze --fatal-infos passed with 0 issues
• dart format verified clean