fix(tvOS): restore focus after closing sidebar

[thiagobrez]

Closes #501.

Summary

• teach the tvOS RepresentableView wrapper to remember its most recently focused descendant and expose it through preferredFocusEnvironments
• reject detached, non-focusable, non-descendant, or Fabric-recycled views whose React tag has changed
• retain the existing default focus path until a descendant has actually been focused
• add a patch changeset and CI checks that lint/typecheck the issue repro and compile the tvOS-only Swift path at the supported tvOS 15.1 deployment target

The implementation is inside #if os(tvOS). iOS, macOS, visionOS, and Android keep the existing wrapper and public APIs/defaults are unchanged.

Validation

• reproduced the issue on tvOS 26.5 with React 19.2.3, react-native-tvos 0.83.1-0, Hermes, and the New Architecture
• rebuilt and ran the final packed library with Xcode 26.6 (17F113), targeting tvOS 15.1
• verified focus restoration to Button 8 over repeated sidebar cycles and to Button 15 after scrolling
• verified a new route starts at Button 0 rather than receiving stale focus, and a fresh install retains the original default entry behavior
• passed yarn lint, yarn typecheck, yarn build, yarn build:ios, and yarn build:android
• passed direct Swift typechecks for tvOS 15.1, iOS 14, macOS 11, and visionOS 1
• passed repro TypeScript/ESLint, workflow YAML, Prettier, changeset, and diff checks

yarn test still exits before executing tests because @bottom-tabs/react-navigation has no test files; this is unchanged from main, and the repository has no test CI job or native XCTest target.

Evidence

• reproduction and environment
• baseline recording
• final fixed recording
• baseline semantic focus and fixed semantic focus
• standalone repro source

Adversarial review

Exactly one synchronous Fable High review covered the full uncommitted diff, including untracked files, and returned six concrete findings. The required one-shot Codex remediation then addressed the recycled-view guard, tvOS CI coverage, release metadata, repro validation/evidence duplication, and Swift style. The Paper-only dynamic-child finding was disproven because old-architecture support was removed in 4b4e781; changing unsupported Paper identity behavior would broaden the fix.

• Fable review JSON
• finding dispositions and remediation validation