uptime-kuma: add uptime_kuma_enabled flag and make monitoring blocks inert

Removing the credentials would otherwise break these playbooks mid-deploy: they
template uptime_kuma_password with no assert to stop them first. 100 tasks are
now guarded by uptime_kuma_enabled (false), so deployments run normally and the
monitoring sections skip. A further 28 tasks were already self-guarding on
monitor_setup/push_url being defined; verified that a skipped task's registered
variable makes those skip cleanly rather than error.

The blocks are kept on purpose — the health-check logic is the durable part and
should be rewired to whatever replaces Uptime Kuma.

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

ansible/services/memos/deploy_memos_playbook.yml

@@ -139,7 +139,18 @@
         msg: "Memos is running on port {{ memos_port }}. Access via Tailscale at http://{{ memos_tailscale_hostname }}:{{ memos_port }}"
 
   handlers:
+    # ═════════════════════════════════════════════════════════════════════════
+    # DEPRECATED — Uptime Kuma was decommissioned on 2026-09-11.
+    #
+    # Every task below is inert: uptime_kuma_enabled is false in
+    # group_vars/all/main.yml, so they all skip and the deployment above still
+    # runs normally. Kept because the health-check logic is the durable part —
+    # when a replacement exists, rewire the push transport and flip the flag.
+    #
+    # What was being monitored: archive/uptime_kuma/MONITORS.md
+    # ═════════════════════════════════════════════════════════════════════════
     - name: Restart memos
+      when: uptime_kuma_enabled | default(false)
       systemd:
         name: memos
         state: restarted
@@ -196,6 +207,7 @@
       command: systemctl reload caddy
 
     - name: Create Uptime Kuma monitor setup script for Memos
+      when: uptime_kuma_enabled | default(false)
       delegate_to: localhost
       become: no
       copy:
@@ -275,6 +287,7 @@
         mode: '0755'
 
     - name: Create temporary config for monitor setup
+      when: uptime_kuma_enabled | default(false)
       delegate_to: localhost
       become: no
       copy:
@@ -288,6 +301,7 @@
         mode: '0644'
 
     - name: Run Uptime Kuma monitor setup
+      when: uptime_kuma_enabled | default(false)
       command: python3 /tmp/setup_memos_monitor.py
       delegate_to: localhost
       become: no
@@ -296,6 +310,7 @@
       ignore_errors: yes
 
     - name: Clean up temporary files
+      when: uptime_kuma_enabled | default(false)
       delegate_to: localhost
       become: no
       file: