Refactor inventory into OS groups and update playbooks accordingly

Group hosts by OS (ubuntu/rocky) in inventory, refactor playbooks to
use group-targeted plays instead of ansible_os_family conditionals,
add bot host, and add Docker volume backup playbook via rsync to storage.

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

playbooks/update_system.yml

@@ -21,33 +21,26 @@
       when: ping_result is not succeeded
       delegate_to: localhost
 
-- name: Update and Upgrade Packages
-  hosts: reachable_hosts
+- name: Update and Upgrade - Ubuntu
+  hosts: ubuntu:&reachable_hosts
   become: true
-  gather_facts: true
+  gather_facts: false
 
   tasks:
-    - name: Update & Upgrade - Debian-based systems
+    - name: Update & Upgrade via apt
       ansible.builtin.apt:
         update_cache: true
         cache_valid_time: 3600
         upgrade: dist
-      when: ansible_os_family == "Debian"
 
-    - name: Update & Upgrade - Modern RHEL-based systems (DNF)
+- name: Update and Upgrade - Rocky Linux
+  hosts: rocky:&reachable_hosts
+  become: true
+  gather_facts: false
+
+  tasks:
+    - name: Update & Upgrade via dnf
       ansible.builtin.dnf:
         name: "*"
         state: latest
-        update_cache: true
-      when:
-        - ansible_os_family == "RedHat"
-        - ansible_pkg_mgr == "dnf"
-
-    - name: Update & Upgrade - Legacy RHEL-based systems (YUM)
-      ansible.builtin.yum:
-        name: "*"
-        state: latest
-        update_cache: true
-      when:
-        - ansible_os_family == "RedHat"
-        - ansible_pkg_mgr == "yum"
+        update_cache: true