feat(demo): edge-to-edge insets, editable fields, mock location, and UX polish

[dkhawk]

Description

This PR refactors and polishes the demo application (:places-compose-demo):

Highlights:

1. Edge-to-Edge & System Insets: Updated MainActivity, PlacesAutocompleteMinimalActivity, LandmarkSelectionActivity, and CommonScreen for full edge-to-edge rendering with Scaffold padding and Material 3 TopAppBar styling.
2. Editable Form Fields & Soft Keyboard: Wired bidirectional state updates on address forms so users can edit fields and trigger the virtual keyboard smoothly.
3. Mock Location Fallback: Added a 1-tap "Use Mock Location Instead" fallback to the location permissions screen, enabling rapid emulator/device verification without needing GPS fixes.
4. Address Descriptors & Landmark UX: Added descriptive empty-state guidance and quick-jump Bangalore KTPO demo shortcut for testing Address Descriptors in supported regions.
5. Lint Cleanup: Fixed PluralsCandidate, removed redundant activity labels, and moved legacy drawable assets.

Part of a stacked PR sequence:

• Base PR: 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)

[googlemaps-bot]

Code Coverage

Overall Project	86.5%	🍏
Files changed	100%	🍏

File	Coverage
AttributionIdInitializer.kt	100%	🍏