Add plugin platform with modular backend and frontend registry.

Split graph/import/meta into Django apps, add API v1 with OpenAPI and pytest, and introduce plugin registry with the tags reference plugin on both FE and BE.

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/graph/services.py

@@ -0,0 +1,66 @@
+from contacts.models import Contact, Relation, NetworkMap, NetworkMapMembership
+
+
+def node_from_contact(contact):
+    return {
+        'id': contact.id,
+        'label': contact.name,
+        'title': '\n'.join(filter(None, [contact.organization, contact.position, contact.email])),
+        'group': contact.organization or 'default',
+    }
+
+
+def node_from_membership(membership):
+    contact = membership.contact
+    return {
+        **node_from_contact(contact),
+        'life_sphere': membership.life_sphere,
+        'network_circle': membership.network_circle,
+        'importance': membership.importance,
+        'map_angle': membership.map_angle,
+        'map_radius_ratio': membership.map_radius_ratio,
+        'membership_id': membership.id,
+    }
+
+
+def edge_from_relation(relation):
+    return {
+        'id': relation.id,
+        'from': relation.source_id,
+        'to': relation.target_id,
+        'label': relation.get_relation_type_display(),
+        'title': relation.description or relation.get_relation_type_display(),
+        'relation_type': relation.relation_type,
+        'interaction_intensity': relation.interaction_intensity,
+    }
+
+
+def build_full_graph():
+    contacts = Contact.objects.all()
+    nodes = [node_from_contact(c) for c in contacts]
+    relations = Relation.objects.select_related('source', 'target').all()
+    edges = [edge_from_relation(r) for r in relations]
+    return {'nodes': nodes, 'edges': edges}
+
+
+def build_network_map_graph(map_id=None):
+    if not map_id:
+        default_map = NetworkMap.objects.order_by('id').first()
+        if not default_map:
+            return {'nodes': [], 'edges': []}
+        map_id = default_map.id
+
+    memberships = list(
+        NetworkMapMembership.objects.filter(map_id=map_id)
+        .select_related('contact')
+        .order_by('contact__name')
+    )
+    allowed_ids = {m.contact_id for m in memberships}
+    nodes = [node_from_membership(m) for m in memberships]
+    relations = Relation.objects.select_related('source', 'target').all()
+    edges = [
+        edge_from_relation(r)
+        for r in relations
+        if r.source_id in allowed_ids and r.target_id in allowed_ids
+    ]
+    return {'nodes': nodes, 'edges': edges}