refactor(global_defaults): extract OS family lists to single source of truth

roles/global_defaults/tasks/main.yml

@@ -14,8 +14,8 @@
 
 - name: Set OS family flags
   ansible.builtin.set_fact:
-    is_rhel: "{{ os in ['almalinux', 'fedora', 'rhel', 'rocky'] }}"
-    is_debian: "{{ os in ['debian', 'ubuntu', 'ubuntu-lts'] }}"
+    is_rhel: "{{ os in os_family_rhel }}"
+    is_debian: "{{ os in os_family_debian }}"
 
 - name: Normalize OS version for keying
   when:

roles/global_defaults/tasks/validation.yml

@@ -114,7 +114,7 @@
   ansible.builtin.assert:
     that:
       - os is defined
-      - os in ["almalinux", "alpine", "archlinux", "debian", "fedora", "opensuse", "rhel", "rocky", "ubuntu", "ubuntu-lts", "void"]
+      - os in os_supported
       - >-
         os not in ["debian", "fedora", "rocky", "almalinux", "rhel"]
         or (os_version is defined and (os_version | string | length) > 0)