Feature: HTMX + Jinja2 Frontend ersetzt Next.js komplett

- Kein Node.js, kein npm, kein Build-Schritt mehr
- HTMX 2.0.4 + PicoCSS 2 vendored in backend/static/
- Jinja2 Templates für alle 9 Seiten (Dashboard, ZFS, Snapshots,
  Shares, Identities, Logs, Services, Navigator, Login)
- HTMX Fragments für Live-Updates (30s Polling Dashboard)
- JWT als httpOnly Cookie statt localStorage
- Disk Usage zeigt TB/PB korrekt (Jinja2 serverseitig formatiert)
- Update-safe: nur Python-Deps, keine npm-Abhängigkeiten

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/templates/snapshots.html

@@ -0,0 +1,46 @@
+{% extends "base.html" %}
+{% block title %}Snapshots – ZMB Webui{% endblock %}
+{% block content %}
+<div style="display:flex;align-items:center;justify-content:space-between;margin-bottom:1rem">
+  <h2 style="margin:0">Snapshots</h2>
+  <small style="color:var(--pico-muted-color)">{{ snapshots|length }} Snapshots</small>
+</div>
+
+{% if not snapshots %}
+<p>Keine Snapshots vorhanden.</p>
+{% else %}
+<div style="overflow-x:auto">
+<table>
+  <thead>
+    <tr>
+      <th>Name</th>
+      <th>Erstellt</th>
+      <th>Belegt</th>
+      <th>Aktionen</th>
+    </tr>
+  </thead>
+  <tbody>
+  {% for snap in snapshots %}
+  <tr id="snap-{{ loop.index }}">
+    <td style="font-family:monospace;font-size:0.85rem">{{ snap.name }}</td>
+    <td>{{ snap.creation }}</td>
+    <td>{{ snap.used }}</td>
+    <td>
+      <div class="actions">
+        <button class="outline secondary"
+                hx-delete="/api/snapshots/{{ snap.name | urlencode }}"
+                hx-confirm="Snapshot {{ snap.name }} löschen?"
+                hx-target="#snap-{{ loop.index }}"
+                hx-swap="outerHTML">Löschen</button>
+        <button class="outline"
+                hx-post="/api/snapshots/{{ snap.name | urlencode }}/clone"
+                hx-swap="none">Klonen</button>
+      </div>
+    </td>
+  </tr>
+  {% endfor %}
+  </tbody>
+</table>
+</div>
+{% endif %}
+{% endblock %}