Jobs: Bewerbungssystem für Social-Media-Manager/in

Backend:
- job_applications + job_application_docs Tabellen in DB
- luna_trial_until Spalte in users (Migration)
- routes/jobs.py: POST /apply (FormData + Datei-Upload, max 3×10MB),
  GET /my-application, GET /luna-trial-status
- Admin: GET/PATCH /admin/applications, GET /admin/applications/{id}/docs/{doc_id}
- Bei Bewerbung: 14-Tage Luna-Probezugang automatisch aktiviert
- Bei Annahme: is_social_media=1 + Gründer-Status gesetzt
- Status-Mails (pending/reviewing/accepted/rejected) via email_html-Template
- auth.py: require_social_media prüft auch luna_trial_until

Frontend:
- pages/jobs.js: Stellenausschreibung + Bewerbungsformular
  (Name, E-Mail, Hund, Social-Handle, Motivation, Datei-Upload)
- Luna-Probezugang Teaser mit Countdown wenn aktiv
- Bestehende Bewerbung: Status-Screen statt Formular
- app.js: 'jobs' Seite registriert
- admin.js: neuer Tab 'Bewerbungen' (filtert nach Status,
  Statuswechsel per Dropdown, Detailansicht mit Anhang-Download,
  Admin-Notiz-Feld)
- admin.js: Tab 'Jobs' → 'Scheduler' umbenannt

backend/main.py

@@ -188,6 +188,7 @@ from routes.breeder_export import router as breeder_export_router
 from routes.zucht_ki       import router as zucht_ki_router
 from routes.partner        import router as partner_router
 from routes.outreach       import router as outreach_router
+from routes.jobs           import router as jobs_router
 
 app.include_router(auth_router,       prefix="/api/auth",       tags=["Auth"])
 app.include_router(dogs_router,       prefix="/api/dogs",       tags=["Hunde"])
@@ -221,6 +222,7 @@ app.include_router(breeder_export_router,  prefix="/api",       tags=["Export"])
 app.include_router(zucht_ki_router,        prefix="/api",       tags=["Züchter-KI"])
 app.include_router(partner_router,         prefix="/api",       tags=["Partner"])
 app.include_router(outreach_router,        prefix="/api/outreach", tags=["Outreach"])
+app.include_router(jobs_router,            prefix="/api/jobs",    tags=["Jobs"])
 app.include_router(webcal_router,     prefix="/api/webcal",     tags=["WebCal"])
 app.include_router(profile_router,    prefix="/api/profile",    tags=["Profil"])
 app.include_router(import_router,          prefix="/api/import",  tags=["Import"])