refactor(cleanup): Phase 1 — delete dead code

Branch: refactor/cleanup-phase-1-dead-code → main

Phase 1 of docs/refactoring/architecture-cleanup-plan.md. It changes no behavior: every deleted file was either fully commented out or empty, and nothing referenced it.

Changes (one commit per step)

Step	Change
2	Delete `lib/core/app_navigation.dart`: old go_router code that was entirely commented out and still referenced `deeptoplay_new`
3	Delete `lib/presentation/pages/noInternet_screen.dart`: commented out, not in the router
4	Delete `lib/presentation/pages/content_pages/ios_video_player.dart`: all 215 lines commented out
5	Delete `lib/data/repositories/app_settings_repository_impl.dart` (0 bytes) and `lib/data/models/app_settings_model.dart` (`AppSettings`, never referenced)
6	Delete `lib/presentation/bloc/connectivity/connectivity_{event,state}.dart`: commented-out `part of` stubs. `ConnectivityCubit` never used them
7	`main.dart`: remove the second, identical copy of the KMS-toggle prefs-restore `try` block

Step 8 (mirror tests) needed no changes, because none of the deleted files had tests.

Verification

fvm flutter analyze: 0 errors and 259 warnings, the same as main. There are two fewer infos, because the deleted files accounted for one file_names and one empty_catches info.
fvm flutter test: 876 passed. The only failures are the two that already fail on main, and they are unrelated to this PR:
- category_screen_test.dart: Songs paints no category strip
- feed_tabs_shell_test.dart: a single-feed shell paints no strip at all
On the iOS Simulator, a debug cold start on a fresh install reached home, with no Flutter exceptions in the log. The home UI was visible behind the system ATT prompt.

🤖 Generated with Claude Code