[a11y][A15] Accessible names not translated #69

Finding

A14 + A15 — Page language and accessible names not localized
Severity: moderate
WCAG: 3.1.1 Language of Page; 1.3.1 Info and Relationships
Theme: both

Bundled: shared root cause (applyChatConfigUI + catalogs). Closes A14 and A15 together.

Where

• A14: public/index.html <html lang="en">; locale at server.js / config
• A15: static aria-labels in public/index.html; Remove ${…} in public/app.js; catalogs i18n/*.json

Current behavior

UI strings can render in Spanish from i18n/es.json, but lang stays en and many control accessible names remain English.

Expected behavior

document.documentElement.lang matches the resolved locale. All chrome accessible names go through t() / catalogs.

Suggested approach

Set lang in applyChatConfigUI. Translate static aria-labels and landmark labels the same way visible labels are. Fix the attachment remove template. Add keys to en.json and es.json.

Acceptance criteria

• language: es sets <html lang="es">
• Static chrome aria-labels and the attachment remove label are translated
• No new hardcoded user-facing accessible names
• Verified with Spanish config
• axe reports no new violations

Reference

a11y-audits/8-5-26/audit.md → findings A14, A15
a11y-audits/8-5-26/wave-4-plan.md → Wave 4c