Rebranding zu NextJobs (nextjobs.cc)

- Markenname 'Bewerbungs-Tracker' -> 'NextJobs' im gesamten UI,
  Footer (incl. nextjobs.cc Copyright), Login, Wortmarke in der
  Top-Navi (Next + Jobs-Gradient), Favicon, Swagger/OpenAPI-Titel,
  CalDAV-PRODID, Browser-Erweiterung (manifest, content, background),
  Runner-Log und Doku.
- Funktionale Begriffe (Bewerbungsunterlagen, -datum etc.) bleiben.
- Docker-Registry (git.hackner.dev) als Infrastruktur unberuehrt.

Co-Authored-By: Claude <noreply@anthropic.com>

lib/api.js

@@ -1,4 +1,4 @@
-// Third-party REST API (v1) for the Bewerbungs-Tracker.
+// Third-party REST API (v1) for the NextJobs.
 //
 // Mounted under /api/v1 in server.js. All endpoints except /health require an
 // API key sent in the X-API-Key header. The key is per-user: it is the