fix: 2.2.0 post-release bug sweep

[2sem]

Goal

Capture regressions and polish gaps found after the 2.2.0 release, then close them in a single stabilization pass for 2.2.1.

Scope

• Reproduce and triage post-release bugs from translation, history, share, speech, and ad-related flows
• Fix only low-risk regressions suitable for a patch release
• Exclude major UX redesigns and new feature work

Acceptance Criteria

• All confirmed 2.2.0 regressions are either fixed or split into follow-up issues
• No new feature scope is added
• Manual QA covers the main user paths before release

Notes

This is the umbrella stabilization issue for 2.2.1.

[2sem]

Triage summary for 2.2.1 patch scope:\n\nPatch-safe candidates:\n- Fix duplicate history saves when re-translating from a history entry (TranslationScreen / HistoryDetailSheet path)\n- Fix save/review triggers firing on non-translation state changes such as language swaps with existing output\n- Fix possible double translation execution from the TranslationViewModel session/configuration path\n- Fix rewarded ad-free state not syncing cleanly with banner visibility at runtime\n- Fix stale speech transcript/error state when reopening speech recognition\n\nDeferred from 2.2.1:\n- History redesign or smarter dedupe behavior\n- Translation pipeline refactors beyond a minimal single-execution guard\n- Broader ad policy redesign\n- Speech UX enhancements beyond reset/safety fixes\n\nRecommended order:\n1. Make save/review/history persistence trigger only on confirmed translation completion\n2. Guarantee a single translation execution per user action\n3. Sync ad-free reward state with banner visibility changes\n4. Reset speech session state cleanly on each new recognition session