ansible: add collect-luks-keys playbook for LUKS backup key archival

New playbook collect-luks-keys.yml connects to all enrolled FreeIPA
clients, checks for /_LUKS_BACKUP_KEY (placed there by the installer
when encryption is enabled), and fetches each key to the Ansible
controller as luks-keys/<HOSTNAME>_LUKS_BACKUP_KEY (mode 0400).

Hosts without the file are reported but not treated as errors.
The luks-keys/ store directory is created with mode 0700.

Usage:
  ansible-playbook -i inventory collect-luks-keys.yml

Can be scheduled via cron on the controller for automatic collection.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

setup/modules/FreeipaAnsible/ansible/collect-luks-keys.yml

@@ -0,0 +1,69 @@
+---
+# collect-luks-keys.yml — fetch LUKS backup keys from enrolled clients.
+#
+# When a client was installed with disk encryption via the M-Archy installer,
+# a backup LUKS key is stored at /_LUKS_BACKUP_KEY inside the encrypted root.
+# This playbook fetches those keys to the controller and names each copy
+# <HOSTNAME>_LUKS_BACKUP_KEY so they can be archived securely.
+#
+# Keys are stored in  luks-keys/  relative to the playbook directory.
+# Protect that directory carefully — keys can unlock client root partitions.
+#
+# Usage:
+#   ansible-playbook -i inventory collect-luks-keys.yml
+#   ansible-playbook -i inventory collect-luks-keys.yml -e luks_keys_store=/secure/path
+#
+# To run automatically, add a cron job on the Ansible controller:
+#   0 3 * * * cd /path/to/playbooks && ansible-playbook -i inventory collect-luks-keys.yml
+
+- name: Collect LUKS backup keys from enrolled clients
+  hosts: all
+  become: yes
+
+  vars:
+    luks_key_path: /_LUKS_BACKUP_KEY
+    luks_keys_store: "{{ playbook_dir }}/luks-keys"
+
+  tasks:
+
+    - name: Ensure local key store directory exists
+      file:
+        path: "{{ luks_keys_store }}"
+        state: directory
+        mode: '0700'
+      delegate_to: localhost
+      run_once: true
+      become: false
+
+    - name: Check for LUKS backup key on client
+      stat:
+        path: "{{ luks_key_path }}"
+      register: luks_key_stat
+
+    - name: Fetch LUKS backup key to controller
+      fetch:
+        src: "{{ luks_key_path }}"
+        dest: "{{ luks_keys_store }}/{{ inventory_hostname }}_LUKS_BACKUP_KEY"
+        flat: yes
+      when: luks_key_stat.stat.exists
+      register: luks_key_fetch
+
+    - name: Secure fetched key permissions
+      file:
+        path: "{{ luks_keys_store }}/{{ inventory_hostname }}_LUKS_BACKUP_KEY"
+        mode: '0400'
+      delegate_to: localhost
+      become: false
+      when:
+        - luks_key_stat.stat.exists
+        - luks_key_fetch is changed
+
+    - name: Report key status
+      debug:
+        msg: >-
+          {{ inventory_hostname }}:
+          {% if luks_key_stat.stat.exists %}
+            key found and fetched to {{ luks_keys_store }}/{{ inventory_hostname }}_LUKS_BACKUP_KEY
+          {% else %}
+            no /_LUKS_BACKUP_KEY present (unencrypted or already collected)
+          {% endif %}