feat: add personal ics feeds for assigned tasks

app/templates/settings/index.html

@@ -95,6 +95,25 @@
     {% endif %}
   </section>
 
+  <section class="panel">
+    <p class="eyebrow">Kalender-Abo</p>
+    <h2>Persönlicher ICS-Feed</h2>
+    <p class="muted">Dieser Read-only-Link zeigt in externen Kalendern nur Aufgaben an, die dir zugewiesen sind. Exportiert werden nur Titel, Beschreibung und Fälligkeitsdatum.</p>
+    <div class="push-box">
+      <div class="field">
+        <label for="calendarFeedUrl">Persönliche Kalender-URL</label>
+        <input id="calendarFeedUrl" type="text" value="{{ calendar_feed_url }}" readonly>
+      </div>
+      <div class="form-actions">
+        <a class="button button--secondary" href="{{ calendar_feed_url }}" target="_blank" rel="noreferrer">ICS öffnen</a>
+        <form method="post" action="{{ url_for('settings.regenerate_calendar_feed') }}">
+          <input type="hidden" name="csrf_token" value="{{ csrf_token() }}">
+          <button type="submit" class="button button--ghost">Link neu erzeugen</button>
+        </form>
+      </div>
+    </div>
+  </section>
+
   {% if current_user.is_admin %}
     <section class="panel">
       <p class="eyebrow">Admin</p>