refactor(phone-app): remove obsolete XML layouts, adapters, and disable ViewBinding

[hungify]

What to build

Clean up legacy XML view files, RecyclerView adapters, and disable ViewBinding after complete migration to Jetpack Compose.

Acceptance criteria

• Remove obsolete layout files (activity_main.xml, activity_settings.xml, item_nav_step.xml, item_place_suggestion.xml).
• Remove obsolete RecyclerView adapters (PlaceSuggestionsAdapter.kt, TurnStepsAdapter.kt) and extension files (TravelModeRadioExtensions.kt).
• Disable viewBinding = true in phone-app/app/build.gradle.kts.
• Ensure full test suite (make test) and Android/ESLint linters (make lint) pass with zero errors.

Blocked by

• feat(phone-app): migrate Settings screen to Jetpack Compose Material 3 #42
• feat(phone-app): migrate Main destination search and navigation UI to Jetpack Compose #43