- Fix orphaned DkvModuleConfig: tenantId pointed to deleted tenant, updated to Default tenant
- DKV controller: return 404 instead of HTTP 200 null when no config exists
- IMAP provider: also detect PDFs sent as application/octet-stream (check filename extension)
- IMAP provider: add seen:false filter so already-processed emails are skipped on re-poll
- IMAP provider: mark email as \Seen after successful PDF download to prevent reprocessing
- Frontend dkv-api: handle 404 from fetchConfig as "not yet configured" (returns null)
- InboxConfigForm: show warning banner when config not yet saved in DB
- InboxConfigForm: add "Jetzt prüfen" button to manually trigger POST /dkv/check-now
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Backend dkv.service.ts returned { imported } but frontend read result.count,
causing the success toast to always display "undefined Fahrzeuge importiert".
Align backend field name to count and update the dkv-api.ts return type to
include mode for completeness.