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/confirm.html

@@ -8,6 +8,13 @@
     <p class="warn">⚠ {{ intro }}</p>
     <div class="preview-box">{{ preview }}</div>
 
+    {% if attachments %}
+      <div class="attach-summary">
+        <strong>Anhänge ({{ attachments|length }}):</strong>
+        {% for name in attachments %}<span class="attach-chip">📎 {{ name }}</span>{% endfor %}
+      </div>
+    {% endif %}
+
     <form method="post" action="{{ action_url }}" class="confirm-actions"
           onsubmit="this.querySelector('button').disabled=true;">
       {% for name, value in fields.items() %}