- New /supply/new-listing page (Path A: pre-filled from portfolio unit,
Path B: standalone blank form); creates EXTERNAL_MARKET + sourceType DIRECT
- "+ Inserat" button on available units in PropertyDetailView navigates
with prefilled address/area/rent
- Nav entry "Neues Inserat" added to supply sidebar
- SourceProvenancePanel hidden for DIRECT source listings (no external source)
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>