i18n(frontend): translate all German UI strings to English
Replace German labels, button text, toast messages, table headers,
tooltips, and placeholder strings across 7 files:
- WorkflowEditor: buttons, toasts, node labels
- Tenants: buttons, toasts, dialog text, table headers
- Admin: widget layout description
- OrderDetail: column headers (Baureihe→Series, Ebene→Level, Lagertyp→Bearing Type)
- ExcelSpreadsheet: column label definitions
- Upload: series/duplicate warning strings
- TemplateEditor: ALL_FIELD_DEFS default labels
API field names (baureihe, ebene1, produkt_baureihe etc.) unchanged.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Hartmut
206672a858