fix(global_defaults): populate flat network fields from interfaces in pre-computed path

roles/global_defaults/tasks/system.yml

@@ -48,6 +48,28 @@
         }, recursive=True)
       }}
 
+- name: Populate primary network fields from first interface (pre-computed)
+  when:
+    - system_cfg is defined
+    - _bootstrap_needs_enrichment | default(false) | bool
+    - system_cfg.network.interfaces | default([]) | length > 0
+    - system_cfg.network.bridge | default('') | string | length == 0
+  vars:
+    _primary: "{{ system_cfg.network.interfaces[0] }}"
+  ansible.builtin.set_fact:
+    system_cfg: >-
+      {{
+        system_cfg | combine({
+          'network': system_cfg.network | combine({
+            'bridge': _primary.bridge | default(''),
+            'vlan': _primary.vlan | default(''),
+            'ip': _primary.ip | default(''),
+            'prefix': _primary.prefix | default(''),
+            'gateway': _primary.gateway | default('')
+          })
+        }, recursive=True)
+      }}
+
 - name: Derive convenience facts from pre-computed system_cfg
   when:
     - system_cfg is defined