build(deps): update dependencies, edge-to-edge insets, and polish demo UX

[dkhawk]

Summary

• Updates dependencies to latest stable versions (AGP 8.9.0, Kotlin 2.1.10, Gradle 8.13, Places 4.1.0, Maps Compose 6.5.3, Compose BOM 2025.02.00).
• Updates GitHub Actions workflows to v4.
• Implements edge-to-edge system bars insets and Material 3 styling.
• Adds mock location permission fallback option.
• Fixes editable text field state in Landmark Selection form.
• Adds regional Address Descriptor guidance banners, preset location jumps, loading feedback, and robust error handling for Geocoding.
• Adds 'Save & Confirm Address' action and activity descriptions in MainActivity.

Testing

• Verified on Android device: all 4 activities function smoothly.
• Ran ./gradlew check test jacocoTestReport with all checks and tests passing.

[googlemaps-bot]

Code Coverage

Overall Project	86.47% -0.05%	🍏
Files changed	87.5%	🍏

File	Coverage
AddressDto.kt	82.68% -0.65%	🍏

[dkhawk]

This PR has been split into a 4-part stack for easier, modular review:

1. ci: pin action SHAs, set permissions, and prevent template injection #115 (ci/workflow-security-hardening): GitHub Actions permissions, action SHA pinning, and template injection prevention.
2. test: add comprehensive test suite for places-compose reaching 93.8% coverage #116 (test/library-coverage-baseline): Comprehensive unit and Compose UI test suite raising project coverage from 6.4% to 93.8%.
3. build(deps): update AGP to 9.3.2, Gradle to 9.5.1, Places SDK to 5.3.0, and Compose BOM #117 (build/dependency-modernization): Dependency and build system modernization (AGP 9.3.2, Gradle 9.5.1, Compose BOM, Places SDK 5.3.0).
4. feat(demo): edge-to-edge insets, editable fields, mock location, and UX polish #118 (demo/ux-edge-to-edge-polish): Demo app edge-to-edge insets, editable form fields, mock location fallback, and UX polish.