Add merge category functionality for admin users with confirmation prompt

sbas/templates/sbas/merge_category.html

@@ -0,0 +1,48 @@
+{% extends 'sbas/base.html' %}
+
+{% block content %}
+  <h2>Merge Category</h2>
+
+  {% if error %}
+    <div class="alert alert-danger">{{ error }}</div>
+  {% endif %}
+
+  {% if success %}
+    <div class="alert alert-success">{{ success }}</div>
+  {% endif %}
+
+  <p>This admin tool will move all questions assigned to the <strong>Source</strong> category into the <strong>Target</strong> category. Optionally you may delete the Source category after the move.</p>
+
+  <form method="post">
+    {% csrf_token %}
+    <div class="mb-3">
+      <label for="id_source" class="form-label">Source category (to be merged)</label>
+      <select name="source" id="id_source" class="form-select">
+        <option value="">-- select source --</option>
+        {% for c in categories %}
+          <option value="{{ c.pk }}">{{ c }}</option>
+        {% endfor %}
+      </select>
+    </div>
+
+    <div class="mb-3">
+      <label for="id_target" class="form-label">Target category (destination)</label>
+      <select name="target" id="id_target" class="form-select">
+        <option value="">-- select target --</option>
+        {% for c in categories %}
+          <option value="{{ c.pk }}">{{ c }}</option>
+        {% endfor %}
+      </select>
+    </div>
+
+    <div class="form-check mb-3">
+      <input class="form-check-input" type="checkbox" value="on" id="id_delete_source" name="delete_source">
+      <label class="form-check-label" for="id_delete_source">
+        Delete source category after merge
+      </label>
+    </div>
+
+    <button type="submit" class="btn btn-danger" onclick="return confirm('Are you sure you want to move all questions from the source to the target category? This action cannot be undone.');">Merge categories</button>
+  </form>
+
+{% endblock %}