Prevent screen turning off during playback & Android 16 SDK

[PiloUnk]

Summary

Two independent smartphone-app fixes, pushed as separate commits on master:

• a0314fb3 — Keep the screen on during channel playback by setting
  WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON directly on
  PlayerActivity's window, instead of relying solely on
  PlayerView.setKeepScreenOn(true). The View-level propagation to the
  window flag is unreliable on some OEM builds (observed on Samsung One UI
  on a Galaxy S23), causing the screen to time out and turn off mid-playback
  even though keepScreenOn was always true in this Activity.
• d63a0299 — Bump app/smartphone's targetSdk from 33 to 36 (Android 16).
  It was left far behind compileSdk (37), which triggers Android's
  install-time "this app may not work well" compatibility warning on recent
  OS versions. samples/ and testing/extension-reference already target 36.

AI Agent Checklist

Before submitting this PR, confirm:

• I identified the task type.
• I read the root AGENTS.md.
• I read all relevant directory-level AGENTS.md files.
• I avoided unrelated refactors.
• I respected module dependency boundaries.
• I did not move low-level data access into UI.
• I did not introduce unnecessary dependencies.
• I ran the smallest relevant validation command.
• I documented any validation that could not be run.
• I listed risks or compatibility concerns.

Instructions Read

List the instruction files read for this change:

• AGENTS.md
• app/AGENTS.md
• docs/ai/playbooks/playback-pipeline.md
• docs/ai/playbooks/apk-size.md
• docs/ai/VALIDATION_MATRIX.md

Validation

Commands run:

./gradlew :app:smartphone:assembleDebug
./gradlew :app:smartphone:assembleRelease

Results:

BUILD SUCCESSFUL — both variants compiled and packaged cleanly with
targetSdk 36 and the window-level keep-screen-on flag.
Release APK: 10.7 MB (R8 minify + resource shrink enabled, as before).

Commands not run:

./gradlew :app:tv:compileDebugKotlin
Manual on-device screen-timeout check on affected OEM (Samsung One UI)

Reason:

- app/tv: neither commit touches any app/tv source or build file; the
  Android TV variant's targetSdk (33) and playback code are unaffected.
- Manual OEM check: verifying the original screen-timeout bug and its fix
  requires a physical device with a real user-configured screen-timeout
  setting, which isn't reproducible in this (headless) environment. The
  fix was validated by code path (window flag set in onCreate, matches
  standard practice for a playback-dedicated Activity) but not re-tested
  live on the reporting device.

Risk Notes

Mention any risk areas:

Playback behavior: PlayerActivity's window now carries
FLAG_KEEP_SCREEN_ON for its whole lifecycle (cleared automatically on
destroy); the existing PlayerView.setKeepScreenOn call is left in place
as a no-op-redundant safeguard, not removed.
API compatibility: targetSdk 36 opts the app into Android
14/15/16 behavior changes gated by targetSdk (e.g. predictive back,
enforced edge-to-edge). Edge-to-edge is already explicitly handled via
enableEdgeToEdge(); other targetSdk-gated behaviors were not
exhaustively audited beyond a successful compile/assemble of both build
types.
Binary size: no dependencies added; release artifact size unchanged
in kind (still minified/shrunk as before).
TV focus behavior / Resource-i18n / Database migration: not applicable,
no app/tv, i18n, or Room changes in either commit.

[oxyroid]

Reverted. Resume old prevent state before leaving playback. And do not change targetSdkVersion.

[PiloUnk]

Indeed, didn't see the various states. Sorry for that!

Would this be better?
PiloUnk@bbb8456