ansible: add reboot playbook and short hostname support

- Add reboot.yml playbook with rolling reboot (serial: 1)
  - Uses systemd reboot.target for NixOS compatibility
  - Waits for each host to come back before proceeding
- Update dynamic inventory to use short hostnames
  - ansible_host set to FQDN for connections
  - Allows -l testvm01 instead of -l testvm01.home.2rjus.net
- Update static.yml to match short hostname convention

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

ansible/inventory/static.yml

@@ -2,9 +2,12 @@
 #
 # Hosts defined here are merged with the dynamic flake inventory.
 # Use this for infrastructure that isn't managed by NixOS.
+#
+# Use short hostnames as inventory names with ansible_host for FQDN.
 
 all:
   children:
     proxmox:
       hosts:
-        pve1.home.2rjus.net:
+        pve1:
+          ansible_host: pve1.home.2rjus.net