Roadmap: tick off tablet layouts and download subtitles

[Ivorisnoob]

Roadmap accuracy pass. Nothing in the app changes.

Why

docs/ROADMAP.md had drifted from the code, which makes it useless for deciding what to build next. Three items were already shipped but still unticked, the 'Already in place' list was missing half of what the app does, and three open items hid prerequisites you only find by reading the code.

What changed

Ticked off, having verified them in the code first:

• Tablet and foldable layouts. Landed in 949a621 but never ticked. Adaptive.kt carries the width class (�yWidth, isCompactWidth, isExpandedWidth, CenteredListBox) and AppNavigation.kt:222 swaps the floating toolbar for a WideNavigationRail on non-compact widths.
• Download subtitles. Landed in PR Offline subtitles for downloads, faster source search, Stremio add-ons #15. The entry now describes what actually shipped: the per-download sheet, the Settings language list, and the storage layout.

Corrected the 'Already in place' list, which was missing SubSource, Chromecast, PiP, profiles with kids filters, per-source ranking and DNS-over-HTTPS.

Annotated three open items with the prerequisite that is easy to miss:

• Trakt / AniList / MAL sync is blocked on a decision. Trakt needs a registered client id and secret, which collides with the 'no user-supplied API keys' rule in CLAUDE.md. AniList is keyless and is the cheap first target if sync is wanted at all.
• New episode notifications needs two things, not one: WorkManager and a follow concept, which does not exist in the app yet.
• Localization is a very large sweep. strings.xml holds 2 entries; essentially all UI text is hard-coded in Compose.

Also verified as genuinely still open

No media3-session dependency, no widget code, no leanback in the manifest, and trailers still open YouTube externally at DetailsScreen.kt:913.

46 ticked, 12 open.

Co-Authored-By: Claude Opus 5.5 noreply@anthropic.com