Add siblings to family tree/genealogy person pages

Enhancements:
- Added siblings field to person data structure
- Calculate siblings by finding people who share parents
- Display siblings section on person pages with count
- Siblings shown between parents and children sections
- Includes same metadata as other relationships (generation, lifespan)

Implementation:
- Third pass in parse_gedcom_to_tree_data() to calculate siblings
- Uses set to avoid duplicates from multiple shared parents
- Template displays sibling count and links to sibling pages

Example: Cain, Abel, and Seth now show as siblings on each other's pages.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

kjvstudy_org/server.py

@@ -3649,6 +3649,7 @@ def parse_gedcom_to_tree_data(gedcom_path):
                 "description": description,
                 "children": [],
                 "parents": [],
+                "siblings": [],
                 "spouse": None,
                 "verses": all_verses,
                 "birth_year": birth_year,
@@ -3695,6 +3696,23 @@ def parse_gedcom_to_tree_data(gedcom_path):
                         if wife_id not in tree_data[child_id]["parents"]:
                             tree_data[child_id]["parents"].append(wife_id)
 
+    # Third pass: calculate siblings
+    # Siblings are people who share at least one parent
+    for person_id, person in tree_data.items():
+        siblings_set = set()
+
+        # Find all people who share a parent with this person
+        for parent_id in person["parents"]:
+            if parent_id in tree_data:
+                # Get all children of this parent
+                for sibling_id in tree_data[parent_id]["children"]:
+                    # Don't include the person themselves
+                    if sibling_id != person_id:
+                        siblings_set.add(sibling_id)
+
+        # Convert set to list and store
+        person["siblings"] = list(siblings_set)
+
     # Calculate generations using BFS from root people (those with no parents)
     generations = {}
     for person_id, person in tree_data.items():

kjvstudy_org/templates/family_tree_person.html

@@ -164,6 +164,26 @@
 </div>
 {% endif %}
 
+{% if person.siblings|length > 0 %}
+<div class="relationships-section">
+    <h2>Siblings ({{ person.siblings|length }})</h2>
+    <div class="relationship-list">
+        {% for sibling_id in person.siblings %}
+            {% if sibling_id in family_tree_data %}
+            <div class="relationship-item">
+                <span class="relationship-name"><a href="/family-tree/person/{{ sibling_id }}">{{ family_tree_data[sibling_id].name }}</a></span>
+                {% if family_tree_data[sibling_id].generation or family_tree_data[sibling_id].age_at_death != "Unknown" %}
+                <span class="relationship-meta">
+                    {% if family_tree_data[sibling_id].generation %}generation {{ family_tree_data[sibling_id].generation }}{% endif %}{% if family_tree_data[sibling_id].age_at_death != "Unknown" %}{% if family_tree_data[sibling_id].generation %}, {% endif %}lived {{ family_tree_data[sibling_id].age_at_death }}{% endif %}
+                </span>
+                {% endif %}
+            </div>
+            {% endif %}
+        {% endfor %}
+    </div>
+</div>
+{% endif %}
+
 {% if person.children|length > 0 %}
 <div class="relationships-section">
     <h2>Children ({{ person.children|length }})</h2>