uptime-kuma: deprecation banners on the monitoring-only plays

These five plus the ntfy notification playbook assert on the credentials, so
they now fail immediately instead of running — deliberately, before anything is
installed. The banner says so and points at archive/uptime_kuma/.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

ansible/infra/410_disk_usage_alerts.yml

@@ -1,3 +1,16 @@
+# ═════════════════════════════════════════════════════════════════════════════
+# DEPRECATED — Uptime Kuma was decommissioned on 2026-09-11.
+#
+# This play WILL FAIL if run as-is, and that is deliberate: uptime_kuma_username
+# and uptime_kuma_password were removed from the vault, so the "Validate Uptime
+# Kuma configuration" assert stops it before anything is installed or changed.
+#
+# It is kept because the CHECK LOGIC is the durable part — what gets measured,
+# the thresholds, and the systemd timer plumbing. When something replaces Uptime
+# Kuma, only the push transport needs rewriting; the rest still applies.
+#
+# What was being monitored: archive/uptime_kuma/MONITORS.md
+# ═════════════════════════════════════════════════════════════════════════════
 - name: Deploy Disk Usage Monitoring
   hosts: managed
   become: yes

ansible/infra/420_system_healthcheck.yml

@@ -1,3 +1,16 @@
+# ═════════════════════════════════════════════════════════════════════════════
+# DEPRECATED — Uptime Kuma was decommissioned on 2026-09-11.
+#
+# This play WILL FAIL if run as-is, and that is deliberate: uptime_kuma_username
+# and uptime_kuma_password were removed from the vault, so the "Validate Uptime
+# Kuma configuration" assert stops it before anything is installed or changed.
+#
+# It is kept because the CHECK LOGIC is the durable part — what gets measured,
+# the thresholds, and the systemd timer plumbing. When something replaces Uptime
+# Kuma, only the push transport needs rewriting; the rest still applies.
+#
+# What was being monitored: archive/uptime_kuma/MONITORS.md
+# ═════════════════════════════════════════════════════════════════════════════
 - name: Deploy System Healthcheck Monitoring
   hosts: managed
   become: yes

ansible/infra/430_cpu_temp_alerts.yml

@@ -1,3 +1,16 @@
+# ═════════════════════════════════════════════════════════════════════════════
+# DEPRECATED — Uptime Kuma was decommissioned on 2026-09-11.
+#
+# This play WILL FAIL if run as-is, and that is deliberate: uptime_kuma_username
+# and uptime_kuma_password were removed from the vault, so the "Validate Uptime
+# Kuma configuration" assert stops it before anything is installed or changed.
+#
+# It is kept because the CHECK LOGIC is the durable part — what gets measured,
+# the thresholds, and the systemd timer plumbing. When something replaces Uptime
+# Kuma, only the push transport needs rewriting; the rest still applies.
+#
+# What was being monitored: archive/uptime_kuma/MONITORS.md
+# ═════════════════════════════════════════════════════════════════════════════
 - name: Deploy CPU Temperature Monitoring
   hosts: hypervisor
   become: yes

ansible/infra/nodito/32_zfs_pool_setup_playbook.yml

@@ -171,6 +171,19 @@
         msg: "ZFS pool {{ zfs_pool_name }} is not in a healthy state"
       when: "'ONLINE' not in final_zfs_status.stdout"
 
+# ═════════════════════════════════════════════════════════════════════════════
+# DEPRECATED — Uptime Kuma was decommissioned on 2026-09-11.
+#
+# This play WILL FAIL if run as-is, and that is deliberate: uptime_kuma_username
+# and uptime_kuma_password were removed from the vault, so the "Validate Uptime
+# Kuma configuration" assert stops it before anything is installed or changed.
+#
+# It is kept because the CHECK LOGIC is the durable part — what gets measured,
+# the thresholds, and the systemd timer plumbing. When something replaces Uptime
+# Kuma, only the push transport needs rewriting; the rest still applies.
+#
+# What was being monitored: archive/uptime_kuma/MONITORS.md
+# ═════════════════════════════════════════════════════════════════════════════
 - name: Setup ZFS Pool Health Monitoring and Monthly Scrubs
   hosts: hypervisor
   become: true

ansible/infra/nodito/34_nut_ups_setup_playbook.yml

@@ -250,6 +250,19 @@
         - nut-monitor
 
 
+# ═════════════════════════════════════════════════════════════════════════════
+# DEPRECATED — Uptime Kuma was decommissioned on 2026-09-11.
+#
+# This play WILL FAIL if run as-is, and that is deliberate: uptime_kuma_username
+# and uptime_kuma_password were removed from the vault, so the "Validate Uptime
+# Kuma configuration" assert stops it before anything is installed or changed.
+#
+# It is kept because the CHECK LOGIC is the durable part — what gets measured,
+# the thresholds, and the systemd timer plumbing. When something replaces Uptime
+# Kuma, only the push transport needs rewriting; the rest still applies.
+#
+# What was being monitored: archive/uptime_kuma/MONITORS.md
+# ═════════════════════════════════════════════════════════════════════════════
 - name: Setup UPS Heartbeat Monitoring with Uptime Kuma
   hosts: hypervisor
   become: true