(CODUX-226) Document dashboard internationalization

[numnx]

🧩 Task: Document dashboard internationalization

Automated task PR opened by Code UX for T26.

📋 Summary

Sprint: Sprint 226 · Dashboard internationalization foundation · Task: T26

Establish a dashboard-only English/German internationalization system with persisted locale selection, complete German coverage across every dashboard route and overlay except English documentation bodies, locale-aware formatting, and automated coverage checks while preserving backend contracts and runtime/API-authored messages verbatim.

🤖 Model & Provider

Provider	Codex CLI
Model	gpt-5.6-sol

⏱️ Timing

Started	2026-07-14 18:47:57 UTC
Finished	2026-07-14 18:53:52 UTC
Duration	5m 55s

📊 Token Usage

Metric	Value
Input tokens	120,140
Cached input tokens	2,221,056
Output tokens	14,194
Total tokens	2,355,390
Invocations	1
Tool calls	27
Active time	5m 39s

Included usage estimate (subscription/local login): $2.14

✅ QA Review

⏳ QA review runs after this PR is opened. Check the task card in the dashboard for the outcome once it lands.

📝 Full Task Prompt

## Objective
Publish accurate English documentation for the completed dashboard internationalization subsystem and user-facing Language selector.

## Scope
- Create `docs/dashboard/internationalization.md`
- Create `docs-web/user/dashboard/internationalization.md`
- Edit `docs/index.md`, `docs/SUMMARY.md`, `docs/dashboard/dashboard-guide.md`, and `docs/dashboard/design-system-settings.md`
- Edit `docs-web/user/dashboard/overview.md` and `docs-web/user/dashboard/settings.md`
- Edit `scripts/sync-docs-web.mjs` to position the new public page in the dashboard documentation order
- Generate and verify corresponding files under `docs-web/content/docs/`, `docs-web/routes/`, and the docs registry using the existing sync script

## Implementation Requirements
1. Document English/German support, English default behavior, the Settings → Appearance Language workflow, immediate browser-local persistence, cross-tab/restart behavior, HTML `lang`, locale-aware formatting, and recovery from invalid/unavailable storage.
2. Document the architecture for typed feature-owned bundles, lazy route loading, interpolation/plural rules, adding a locale, test expectations, and the static-copy guardrail.
3. State the boundaries explicitly: backend/API/MCP contracts are unchanged; provider/runtime/user-authored content is rendered verbatim; the internal Docs viewer chrome is localized but English documentation bodies, titles, and source content remain English.
4. Link the new page from both canonical indexes and public dashboard pages, then regenerate public MDX/routes/registry rather than editing generated mirrors by hand.

## Constraints
- Keep documentation itself in English as required by the sprint exception.
- Do not claim automatic browser-language detection, backend synchronization, or additional locales that were not implemented.
- Do not claim validation passed unless the corresponding command succeeds.
- Follow existing docs-web link and generation conventions.

## Verification
- Run `pnpm run sync:docs-web`.
- Run `pnpm run check:docs-web`.
- Run `rg -n "internationalization|Language|Deutsch|runtime/API|English documentation" docs/dashboard docs/index.md docs/SUMMARY.md docs-web/user/dashboard docs-web/content/docs`.
- Run `pnpm run lint`.
- Run `pnpm run build`.
- Success means canonical and public documentation are linked, generated mirrors are synchronized, and the documented behavior matches the tested implementation.

🌿 Branch Info

Base: feature/CODUX-226-dashboard-internationalization-foundation
Head: task/feature-codux-22-t26-codex-617e61fa-mrl07kb8

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🤖 Generated by Code UX