feat(global_defaults): add os_family_map and os_family fact for platform config lookups

roles/global_defaults/defaults/main.yml

@@ -9,6 +9,22 @@ os_family_debian:
   - debian
   - ubuntu
   - ubuntu-lts
+
+# OS → family mapping — aligns with the main project's ansible_os_family pattern.
+# Enables platform_config dict lookups per role instead of inline when: is_rhel chains.
+os_family_map:
+  almalinux: RedHat
+  alpine: Alpine
+  archlinux: Archlinux
+  debian: Debian
+  fedora: RedHat
+  opensuse: Suse
+  rhel: RedHat
+  rocky: RedHat
+  ubuntu: Debian
+  ubuntu-lts: Debian
+  void: Void
+
 os_supported:
   - almalinux
   - alpine

roles/global_defaults/tasks/main.yml

@@ -20,6 +20,7 @@
   ansible.builtin.set_fact:
     is_rhel: "{{ os in os_family_rhel }}"
     is_debian: "{{ os in os_family_debian }}"
+    os_family: "{{ os_family_map[os] | default('Unknown') }}"
 
 - name: Normalize OS version for keying
   when: