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/_layout.html

@@ -21,7 +21,6 @@
         <a class="tab {% if active_tab=='wohnungen' %}active{% endif %}" href="/">Wohnungen</a>
         <a class="tab {% if active_tab=='bewerbungen' %}active{% endif %}" href="/bewerbungen">Bewerbungen</a>
         <a class="tab {% if active_tab=='logs' %}active{% endif %}" href="/logs">Logs</a>
-        <a class="tab {% if active_tab=='fehler' %}active{% endif %}" href="/fehler">Fehler</a>
         <a class="tab {% if active_tab=='einstellungen' %}active{% endif %}" href="/einstellungen">Einstellungen</a>
     </nav>
 </header>