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>

views/partials/head.ejs

@@ -1,7 +1,7 @@
 <meta charset="UTF-8">
 <meta name="viewport" content="width=device-width, initial-scale=1.0">
 <meta name="theme-color" content="#2563eb">
-<title>Bewerbungs-Tracker</title>
+<title>NextJobs</title>
 <link rel="icon" type="image/svg+xml" href="/favicon.svg">
 <!-- Apply the dark class before first paint to avoid a light-mode flash (FOUC).
      Theme follows the browser/OS setting (prefers-color-scheme) — no manual toggle. -->