Add EPI-Support monitoring & analytics platform

Internal Flask app that monitors the epi-helpdesk.zammad.com tickets via
the Zammad API, deployable as a systemd service behind Apache under
/episupport.

Features:
- Poller: session-login API sync, snapshot diff to detect agent changes
  (status, owner, priority, closures, new replies); email notifications
- Dashboard: ticket overview with sorting, "not closed" filter and
  highlighting of tickets with unconfirmed changes; per-item and bulk
  "mark as read"
- Analytics: KPIs, response/resolution times, monthly SVG trend chart,
  distributions (status/priority/group/agent), Excel export
- Conversation view: full per-ticket thread cached in the DB (avoids
  proxy timeouts), inline image attachments, safe HTML-to-text rendering
- Write actions: reply to tickets and create new tickets with a
  confirmation step and attachment upload (incl. clipboard paste);
  self-triggered actions are synced back so they aren't flagged as changes
- Local timezone display (Europe/Berlin) for all timestamps

Includes deploy tooling: setup.sh, systemd units and Apache config.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

templates/new_ticket.html

@@ -6,7 +6,8 @@
 
 <section class="panel">
   <div class="panel-head"><h2>Neues Ticket beim EPI-Support anlegen</h2></div>
-  <form method="post" action="{{ url_for('new_ticket_preview') }}" class="form">
+  <form method="post" action="{{ url_for('new_ticket_preview') }}"
+        class="form attach-form" enctype="multipart/form-data">
     <label>Titel / Betreff
       <input type="text" name="title" required maxlength="200"
              placeholder="Kurze Zusammenfassung des Anliegens">
@@ -20,11 +21,13 @@
     </label>
     <label>Nachricht
       <textarea name="body" rows="10" required
-                placeholder="Beschreibe dein Anliegen…"></textarea>
+                placeholder="Beschreibe dein Anliegen… (Screenshot mit Strg+V einfügen)"></textarea>
     </label>
+    {% include "_attach.html" %}
     <div class="form-actions">
       <button class="btn-sm" type="submit">Weiter zur Bestätigung →</button>
     </div>
   </form>
 </section>
 {% endblock %}
+{% block scripts %}<script src="{{ url_for('static', filename='upload.js') }}"></script>{% endblock %}