Add repo foundation: proxmox/lxc/vms groups, ansible.cfg, collections, lint configs

- inventory: add proxmox host, lxc and vms groups, critical_services per host
- retarget bootstrap and time-region to ubuntu:rocky so the Proxmox host is untouched
- add ansible.cfg, collections/requirements.yml, .gitignore, .yamllint, .ansible-lint
- remove stale root new_lxc.yml duplicate and the Nextcloud upgrade playbook

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01JEczyvRjfakkiDNkbZA7PR

inventories/all.yml

@@ -1,3 +1,17 @@
+# Homelab inventory.
+#
+# Group layout:
+#   ubuntu   - Ubuntu LXC containers and VMs
+#   rocky    - Rocky Linux 9 LXC containers
+#   proxmox  - the Proxmox VE host
+#   lxc      - the subset of ubuntu/rocky hosts that are LXC containers
+#   vms      - the subset of ubuntu/rocky hosts that are QEMU VMs
+#
+# A host may belong to several groups. Define ansible_host once, under the OS
+# group; lxc/vms list names only. Entries marked PLACEHOLDER need real values.
+#
+# critical_services is read by playbooks/service_check.yml.
+---
 all:
   vars:
     ansible_user: root
@@ -6,15 +20,39 @@ all:
       hosts:
         webserver:
           ansible_host: 192.168.55.10
+          critical_services:            # PLACEHOLDER: verify service names
+            - nginx
         docker:
           ansible_host: 192.168.55.11
+          critical_services:
+            - docker
+            - containerd
+        # ubuntu-vm1:                    # PLACEHOLDER: first Ubuntu VM, also list under vms
+        #   ansible_host: 192.168.2.XXX
+        #   critical_services: []
     rocky:
       hosts:
         pihole:
           ansible_host: 192.168.2.2
+          critical_services:
+            - pihole-FTL
         bot:
           ansible_host: 192.168.2.174
+          critical_services: []         # PLACEHOLDER: add the bot's service name
         storage:
           ansible_host: 192.168.2.115
-        # nextcloud:
-        #   ansible_host: 192.168.2.120
+          critical_services: []         # PLACEHOLDER: e.g. nfs-server, smb
+    proxmox:
+      hosts:
+        pve:
+          ansible_host: 192.168.2.254   # PLACEHOLDER: verify
+    lxc:
+      hosts:
+        webserver:
+        docker:
+        pihole:
+        bot:
+        storage:
+    vms:
+      hosts:
+        # ubuntu-vm1:                    # PLACEHOLDER: uncomment together with the ubuntu entry above