Refactor NormalCase model to use age_days instead of age_years, update forms, filters, and templates accordingly for improved age handling

atlas/templates/atlas/normals_list.html

@@ -32,7 +32,7 @@
               <small class="text-muted">{{ normal.added_date|date:"Y-m-d" }}</small>
             </div>
             <p class="mb-1">
-              Age: {{ normal.age_years|default:"unknown" }} yrs
+              Age: {{ normal.display_age }}
               {% if normal.examination %} • Exam: {{ normal.examination }}{% endif %}
               {% if normal.modality %} • Modality: {{ normal.modality }}{% endif %}
             </p>

atlas/templates/atlas/partials/_normal_row.html

@@ -3,7 +3,7 @@
     <h5 class="mb-1"><a href="{{ normal.case.get_absolute_url }}">{{ normal.case.title }}</a></h5>
     <small>{{ normal.added_date|date:"Y-m-d" }}</small>
   </div>
-  <p class="mb-1">Age: {{ normal.age_years|default:"unknown" }} years</p>
+  <p class="mb-1">Age: {{ normal.display_age }}</p>
   <p class="mb-1">Examination: {{ normal.examination }} | Modality: {{ normal.modality }}</p>
   {% if normal.notes %}
     <p class="mb-0">Notes: {{ normal.notes }}</p>

atlas/templates/atlas/partials/_normal_toggle.html

@@ -3,7 +3,7 @@
 <div id="normal-toggle-block">
   {% if case.normal_case %}
     <span class="badge bg-success">Normal</span>
-    <small class="text-muted">{% if case.normal_case.age_years %}{{ case.normal_case.age_years }}y{% else %}age unknown{% endif %}</small>
+    <small class="text-muted">{{ case.normal_case.display_age }}</small>
     {% if can_mark_normal %}
       <button class="btn btn-sm btn-outline-danger ms-2"
               hx-post="{% url 'atlas:case_toggle_normal' case.pk %}"