fix: re-gather facts after reboot to detect target OS package manager

The live ISO (Arch) caches ansible_pkg_mgr=pacman. After rebooting
into the target OS (e.g. Debian), package module fails because pacman
is not available. Re-gather minimal facts including pkg_mgr.

main.yml

@@ -154,6 +154,15 @@
         ansible_ssh_extra_args: "-o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no"
         ansible_python_interpreter: /usr/bin/python3
 
+    - name: Re-gather facts for target OS after reboot
+      when:
+        - post_reboot_can_connect | bool
+      ansible.builtin.setup:
+        gather_subset:
+          - "!all"
+          - min
+          - pkg_mgr
+
     - name: Install post-reboot packages
       when:
         - post_reboot_can_connect | bool