Add phase 3: comments and cooking mode

- Comments on visible recipes; author and admin may delete; per-user
  hourly rate limit (COMMENT_RATE_LIMIT_PER_HOUR)
- Cooking mode with large text, tick-off checklists, serving scaling and
  Screen Wake Lock to keep the display on
- Serving calculator auto-submits on change
- Privacy tests cover comment and cooking-mode URLs

Co-Authored-By: Claude Opus 5.5 <[email protected]>

templates/recipes/cook.html

@@ -0,0 +1,35 @@
+{% extends "base.html" %}
+{% block title %}Kochmodus: {{ recipe.title }}{% endblock %}
+{% block content %}
+<div class="cook" data-wakelock>
+  <div class="page-head">
+    <h1>{{ recipe.title }}</h1>
+    <a class="button secondary" href="{% url 'recipes:detail' recipe.pk %}">Fertig</a>
+  </div>
+  <p class="muted wakelock-status" hidden>Bildschirm bleibt an.</p>
+
+  <section class="card">
+    <div class="section-head">
+      <h2>Zutaten</h2>
+      {% include "recipes/_servings.html" %}
+    </div>
+    {% for group, items in ingredient_groups %}
+      {% if group %}<h3>{{ group }}</h3>{% endif %}
+      <ul class="checklist">
+        {% for ing in items %}
+        <li><label><input type="checkbox"> <span><strong>{{ ing.amount }} {{ ing.unit }}</strong> {{ ing.name }}{% if ing.note %}, {{ ing.note }}{% endif %}</span></label></li>
+        {% endfor %}
+      </ul>
+    {% endfor %}
+  </section>
+
+  <section class="card">
+    <h2>Zubereitung</h2>
+    <ol class="checklist steps-big">
+      {% for step in steps %}
+      <li><label><input type="checkbox"> <span><span class="step-no">{{ forloop.counter }}.</span> {{ step.text|linebreaksbr }}</span></label></li>
+      {% endfor %}
+    </ol>
+  </section>
+</div>
+{% endblock %}