i18n: add translations for remaining fixed German strings

[pixelspark]

What does this PR do?

Fixes some missing translations.

Why?

My German is not so good :-)

Closes #

Checklist

• npm test -- --runInBand passes (all tests green)
• [NA] New module: store + route + test file added
• No secrets or credentials in code
• escHtml() used for all user input rendered to HTML
• [NA] Soft-delete implemented (no hard-delete without admin permanent-delete action)
• CONTRIBUTING.md guidelines followed

Test Evidence

TTest Suites: 15 passed, 15 total
Tests:       229 passed, 229 total
Snapshots:   0 total
Time:        2.01 s
Ran all test suites.