fix(schema): IPAddress.interface - replace Parent with Attribute kind

Parent relationships cannot be optional in Infrahub. Since an IP address
can exist without being assigned to an interface (reserved, planned),
we use kind: Attribute instead of kind: Parent.

Also change InfraInterface.ip_addresses from Component to Generic
since Component requires a matching Parent on the other side.

Both sides now use explicit identifier: interface__ip_addresses
for proper bidirectional linking.

schemas/base.yml

@@ -33,8 +33,9 @@ generics:
         optional: false
       - name: ip_addresses
         peer: InfraIPAddress
+        identifier: interface__ip_addresses
         cardinality: many
-        kind: Component
+        kind: Generic
 
 nodes:
   # ==========================================================================
@@ -360,6 +361,7 @@ nodes:
     relationships:
       - name: interface
         peer: InfraInterface
+        identifier: interface__ip_addresses
         cardinality: one
         optional: true
-        kind: Parent
+        kind: Attribute