Alpha Rolling Build (cf9cc61)

feat(cicd): configure unified signing keystore, 3-tier branch release workflow and about card

Changes & Fix Notes:

• 🚀 Feature: Implemented 3-Tier multi-branch release workflow in GitHub Actions (main=Stable Latest, dev=Beta, alpha=Rolling Pre-release).
• 🚀 Feature: Added interactive 'About Phone Control' card in Settings with live app version, build number, channel badge, CPU architecture, root diagnostics, and direct GitHub Releases link.
• 🔒 Security: Configured unified Zero-Conflict release keystore (phonecontrol-release.jks) across local PC and GitHub Actions to eliminate signature mismatch errors.
• 🛡️ Guardrails: Added keystore patterns to .gitignore to ensure cryptographic keys are never leaked to public git repositories.

Modified Files:

• .github/workflows/android.yml: Multi-channel release logic and base64 keystore decoding.
• .gitignore: Ignored keystore files and directory.
• app/build.gradle.kts: Unified signingConfig for release and debug builds.
• app/src/main/res/layout/activity_settings.xml: Added About Phone Control card layout.
• app/src/main/java/com/example/phonecontrol/SettingsActivity.kt: Implemented setupAboutCard logic.