feat(tui): translation picker with persistent indicator and fuzzy filter

[ivanmaierg]

Summary

Adds the ability to change Bible translation from inside the TUI. Press t in the reader to open an overlay listing translations from the helloao API, filter by typing, pick with Enter, and the passage re-fetches under the new translation. The active translation name renders in the reader header at all times so you always know what you're reading.

• New Translation domain type + branded TranslationId flow end-to-end
• getTranslations added to the BibleRepository port; helloao adapter implements it with a session-scoped closure cache (one fetch per run)
• getChapter / getPassage use cases promoted: translationId is now an explicit parameter (CLI passes DEFAULT_TRANSLATION_ID; TUI passes from ReaderState)
• ReaderState variants loading/loaded/network-error carry translationId + translationName; loaded gains a translationPicker sub-state machine (loading | ready | error)
• 8 new reducer actions cover open, fetch success/failure, query typing, navigation, accept, dismiss
• Substring filter over name + languageEnglishName, lowercase; cap 50 visible items (no virtualization in OpenTUI)
• Overlay component matches the chapter-picker UX precedent (accent color, dim chrome, single accent rule)

Scope

In v1: picker overlay, t shortcut, persistent header indicator, substring fuzzy filter, session cache, full passage re-fetch on switch.

Deferred (separate slices): favorites section, cross-run persistence, RTL text rendering, fzf-grade ranked scoring.

SDD artifacts

• openspec/changes/translation-picker/proposal.md
• openspec/changes/translation-picker/spec.md — 49 REQs
• openspec/changes/translation-picker/design.md — state machine, ADRs, key-routing diagram
• openspec/changes/translation-picker/tasks.md — 47 work-unit tasks, Red/Green TDD pairs
• openspec/changes/translation-picker/verify-report.md — pass with 4 WARNINGs, 0 CRITICAL

Size note

~2,170 lines changed (production + tests + openspec docs). `tasks.md` flagged this as a high review-budget risk and recommended a chained PR along the getChapter signature-break seam. Shipping as a single PR (`size:exception`) since the signature break and its UI consumer must land together for the feature to deliver any value, and this is a solo repo where round-trip cost > review surface cost. The breaking-change seam is isolated to commit `2a218f0` and is reviewable on its own.

Verify report — known deviations

• W-01: Filter field is languageEnglishName (display name) not language (ISO code). Functional improvement; spec text drifted from intent — code is correct, spec needs to follow.
• W-02: Gate order in driver is translation-picker → verse-picker. Spec text reversed them; code is correct per the modal contract.
• W-03, W-04: Test quality debt on the useTranslationsFetch hook test and three type-only assertions in reader-screen.test.ts. Non-blocking.

Test plan

• `bun test` — 285 / 285 passing
• `bunx tsc --noEmit` — clean
• Manual: launch `bun run dev`, navigate to John 3, press `t`, type "king james", `Enter` → passage re-fetches, header reads "King James Version"
• Manual: press `t`, `Esc` → overlay dismissed, no state change
• Manual: open picker with network down → error state renders, `Esc` dismisses
• Manual: open picker twice in one session → second open is instant (session cache)