feat(desktop): add German (de) locale

[goetterbote2342]

Summary

Adds German (de) as a fully translated locale for the Hermes Desktop app, alongside the existing en / zh / zh-hant / ja / ar locales. German is a new language — it was previously not selectable at all.

Changes

File	Change
apps/desktop/src/i18n/de.ts	New — complete German bundle via defineLocale(), covering every top-level section of the en catalog (~2,600 string keys, including the 72 settings field labels and 30 field descriptions)
apps/desktop/src/i18n/languages.ts	de added to LOCALE_OPTIONS + LOCALE_ALIASES (de, de-DE, de-AT, de-CH, german, deutsch)
apps/desktop/src/i18n/types.ts	Locale union extended with 'de'
apps/desktop/src/i18n/catalog.ts	de registered in TRANSLATIONS
apps/desktop/src/i18n/languages.test.ts	Coverage for the new locale + aliases (previous tests asserted de was unsupported)
apps/desktop/src/plugins/kanban/i18n.ts	German bundle for the Kanban plugin (167 keys, matches en)

Quality notes

• Structure validated: every translated key-path was programmatically checked against en.ts and the FIELD_LABELS / FIELD_DESCRIPTIONS trees in constants.ts — no typos in key names, string/function/object shapes match the Translations type 1:1, and all 38 top-level sections are covered. Untranslated keys would fall back to English via the existing runtime fallback (translateFrom), but none are left.
• Grammar/consistency: informal "du" throughout, German plural handling in count templates, German date/day names in the cron scheduler, quotes as „…“.
• Tests: languages.test.ts updated for the new locale; no other tests hard-code the locale list (verified by search).

Notes

I could not run tsc/vitest locally (no Node runtime on this machine), so the type check and i18n test suite are pending on CI.

[alt-glitch]

This was generated by AI during triage.

Duplicate of #51762: both PRs add the same Desktop German locale through de.ts, locale registration, picker aliases, and tests. #51762 is the earlier open implementation.

[goetterbote2342]

Local verification (before CI)

I got a Node runtime onto the machine and ran the checks locally:

• tsc --noEmit (TypeScript 5.9, strict): ✅ exit 0 — de.ts is type-conformant against TranslationOverrides via defineLocale(), all touched files compile, and the Kanban de bundle matches KanbanMessages 1:1 (167/167 keys).
• vitest run (Node 24): ✅ 11/11 tests passed — languages.test.ts (4 tests, including the new de alias/locale assertions) and runtime.test.ts (7 tests, unchanged behavior).
• Structural check (script): every one of the ~2,900 translated key-paths exists in en.ts / constants.ts with matching string/function/object shapes.

The isolated setup used ambient stubs for unrelated external packages (icons, query libs) — none of the stubs touched the translation files themselves.

[goetterbote2342]

Quick note on the duplicate label: this PR and #51762 do overlap in intent (German desktop locale), but they're not identical — this one additionally covers the Kanban plugin bundle (src/plugins/kanban/i18n.ts, all 167 KanbanMessages keys), which #51762 doesn't touch.

I've posted a comparison over there (#51762 (comment)) proposing that whichever PR the maintainers prefer becomes the base and the Kanban translation from the other lands as a follow-up. Happy to rebase, split out the Kanban part as its own PR, or close if #51762 merges as-is with a follow-up planned — whatever is easiest for review.

[goetterbote2342]

Scope update after rebasing onto current main (7a59ece):

The core desktop German locale this PR originally added — de.ts, catalog.ts, languages.ts, types.ts — has since landed upstream on its own, so those files are no longer part of this PR. What remains is the gap that is still open: the Kanban plugin bundle, where KANBAN_LOCALES is still { en, ja, zh, 'zh-hant' } only.

The de bundle was brought up to the current KanbanMessages shape rather than kept at its August state:

• 200/200 key parity with en — adds the 24 keys added upstream since submission (notify.* block, board import/export/rename/switch titles, …)
• drops 3 keys that no longer exist in the interface
• select now takes the primary-modifier argument

tsc --noEmit is clean for src/plugins/kanban/i18n.ts. Given the core locale is on main now, the duplicate label no longer describes what's left — this is the remaining locale gap for the Kanban surface.