v0.50.264 — ja locale, IME Safari fix, fence regex anchoring

Three contributor PRs ship this release:

🇯🇵 Japanese locale (#1439)

@snuffxxx added Japanese (ja) as the 8th built-in UI locale. 825 keys translated to natural, concise Japanese — kanji + hiragana + katakana mix, technical terms in their commonly-used Japanese form (Cronジョブ, MCPサーバー, APIキー, トークン), terse 体言止め style matching the brevity of the English originals (設定, 保存, キャンセル).

Full key parity with English (zero missing, zero extra), all ${var}/{0}-style placeholders preserved, all 26 arrow-function values mirrored with parameter names intact. Settings → Language picker auto-discovers via Object.entries(LOCALES).

🛠 IME composition Enter on Safari (#1441)

@ryan-remeo fixed Japanese/Chinese/Korean users on Safari being unable to compose into the message field. The existing e.isComposing guard worked on Chrome/Firefox but failed on Safari, where the committing keydown for IME confirmation fires AFTER compositionend with isComposing=false. New _isImeEnter(e) helper combines three guards (e.isComposing, e.keyCode===229, manual _imeComposing flag) and is used in both the autocomplete-dropdown Enter path and the send-Enter path. No behavior change for non-IME users.

📝 Markdown renderer fence anchoring (#1440, fixes #1438)

Reported by Cygnus (Discord, May 1) via @AvidFuturist. Triple backticks inside a code block's content (regex with ``` in lookbehind, scripts that document fences, embedded markdown-in-markdown) terminated the outer fence at the wrong place, leaking content into bold/italic passes that ate * characters and produced literal </strong> tags in the output.

Fix anchors all 4 fence regex sites per CommonMark §4.5 — opening fence must start a line (with up to 3 spaces of indent), closing fence must also start a line.

Pre-release Opus advisor follow-up

• _imeComposing blur reset — Opus caught a recoverable footgun in PR #1441's manual flag: if focus is lost mid-composition (window blur or older Safari WebKit IME quirk), compositionend may never fire and the flag stays stuck at true until page reload. Added a blur listener on #msg that also resets the flag.

Two follow-up issues filed for separate PRs:

• #1442 — Server-side _LOGIN_LOCALE parity for ja, pt, ko (login page falls back to English)
• #1443 — Promote _isImeEnter helper to 6 other Safari-affected Enter guards

Tests

3692 passing (+14 new from this batch + 20 from #1440). Browser sanity: 20 + 11 API checks green.

Contributors

• @snuffxxx (#1439 — Japanese locale)
• @ryan-remeo (#1441 — IME Safari fix)
• @nesquena-hermes (#1440 — fence regex)

Reported by Cygnus (Discord, fixed via #1440 → closes #1438).

Full diff: v0.50.263...v0.50.264