First month of code — 3-way i18n and integrations grown up | Stacktube

🇰🇷🇯🇵🇺🇸 Korean, Japanese, and English shipped together

next-intl v4.9.0 — middleware-based locale detection plus a LanguageSwitcher (KO | JA | EN).
Full Japanese transcreation of the UI, legal pages, and SEO/GEO surfaces (Sessions 61–63).
English transcreation — 888 keys (Phase 4-EN-B), plus the English landing, terms, privacy, and refund policy.
Emails in three languages — analysis-done, digest, and billing notifications now arrive in each user's language.
Output language auto-detected — analysis notes follow the UI language by default (Japanese UI → Japanese notes).

Backfill of past notes — when you add a channel, you can analyze its past videos in one pass.
Cancel a backfill — stop a running backfill from the UI.
Partial retry for failed items — retry only the videos that failed, not the entire backfill.
Liveness UI — integration connection state is reported in real time.
Kindle defense UI (3-tier) for Amazon approved senders, to avoid silent rejection.
reMarkable email migration guide as a 3-tier card, cutting the first-setup time.

mark.js — 99.5% highlight match rate inside notes (foundation laid before S75).
Cascading match — needle length steps down 60 → 40 → 25 → 15 characters on retry.
S8 deep links — jump from a search hit straight to the matching paragraph.
Hybrid search infrastructure (S67-C-1) — keyword + vector together, shipped behind a flag.

OAuth state CSRF protection — Drive and Dropbox callbacks are verified by a signed nonce.
opengraph-image per locale — ko/ja/en each get their own slogan image.
Bidirectional hreflang + x-default in the sitemap, keeping ko ↔ ja ↔ en consistent for SEO.
AI crawler readiness — llms-en.txt, BreadcrumbList, favicon, and manifest in place.