refactor: refresh phone UI

[Foxpace]

Summary

Refreshes the phone UI and keeps this work stacked on #98.

• Reworks onboarding, source selection, measurement setup, sensor details, previews, settings, and active recording around the same row-based layout and shared app bars.
• Adds automatic, light, and dark theme modes with optional Android dynamic colors and matching system bars.
• Replaces obsolete onboarding and sensor artwork with tintable vector drawables.
• Moves diagnostics into a dedicated log screen and disables viewing or sharing when no logs exist.
• Returns to the source screen after a measurement stops successfully.
• Updates Android Gradle Plugin from 9.3.1 to 9.3.2.

Verification

• ./gradlew :app:testDebugUnitTest :app:assembleDebug :app:detekt
• git diff --cached --check

Both passed.