ui: live timers, Berlin timestamps, ZIP failure reports, drop kill-switch/Fehler tab

* remove the kill-switch: auto-apply toggle is the single on/off; manual
  'Bewerben' button now only gated by apply reachability; circuit breaker
  stays but only gates auto-apply (manual bypasses, so a user can retry)
* Berlin-timezone date filter (de_dt) formats timestamps as DD.MM.YYYY HH:MM
  everywhere; storage stays UTC
* Wohnungen: live 'entdeckt vor X' on every flat + 'nächste Aktualisierung in Xs'
  countdown in the header, driven by /static/app.js; HTMX polls body every 30s
* drop the Fehler tab entirely; failed applications now carry a
  'Fehler-Report herunterladen (ZIP)' link -> /bewerbungen/{id}/report.zip
  bundles application.json, flat.json, profile_snapshot.json, forensics.json,
  step_log.txt, page.html, console/errors/network JSONs, and decoded
  screenshots/*.jpg for AI-assisted debugging
* trim the 'sensibel' blurb from the Profil tab

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

web/templates/base.html

@@ -7,6 +7,7 @@
     <title>{% block title %}lazyflat{% endblock %}</title>
     <script src="https://cdn.tailwindcss.com"></script>
     <script src="https://unpkg.com/htmx.org@2.0.3"></script>
+    <script src="/static/app.js" defer></script>
     <style>
         :root {
             --bg-from: #e4f0fb; --bg-to: #f7fbfe;