fix(feedback): inline edit + live status change without reload

- Replaced broken status_aendern (missing status_choices in response)
  with a single eintrag_bearbeiten view that always returns the full
  partial context
- eintrag_zeile.html is now a <tbody x-data="{ editing: false }"> with
  two rows: display row + collapsible edit form
- Click anywhere on a row to expand the edit form; @click.stop on the
  status cell prevents accidental toggles
- Status dropdown in the display row posts via HTMX and swaps the whole
  <tbody> — no page reload needed
- Edit form covers all fields: titel, beschreibung, kategorie,
  dringlichkeit, status, bewertung, entscheidung

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

vergabe_teilnahme/templates/feedback/backlog.html

@@ -43,11 +43,9 @@
         <th class="pb-2 font-medium text-slate-600">Datum</th>
       </tr>
     </thead>
-    <tbody>
-      {% for eintrag in eintraege %}
-      {% include "feedback/partials/eintrag_zeile.html" with status_choices=status_choices %}
-      {% endfor %}
-    </tbody>
+    {% for eintrag in eintraege %}
+    {% include "feedback/partials/eintrag_zeile.html" %}
+    {% endfor %}
   </table>
   {% else %}
   <p class="text-slate-500 text-sm">Keine Einträge gefunden.</p>