fix(sys-stk-front-proxy): probe the queued vhosts only on the OpenResty host

sys-stk-full includes the front proxy with run_once and delegate_to, so every set_fact inside is broadcast to all hosts of the play. A worker context queued the clearnet URL (its group_names lack svc-net-tor) over the manager's onion queue, and the deferred probe then ran on every host: workers and the NFS server, which serve nothing and cannot resolve .onion, answered -1 and failed the swarm deploy with 'OpenResty does not serve ... even after a restart' after a needless OpenResty restart. Only the stack host now queues a vhost, and only the first host of svc-prx-openresty probes the queue; an empty queue skips before the group is read.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

roles/sys-stk-front-proxy/tasks/deferred_probe.yml

@@ -1,6 +1,8 @@
 ---
 - name: "🔍 Probe the vhosts this play queued"
-  when: front_proxy_deferred_probes | length > 0
+  when:
+    - front_proxy_deferred_probes | length > 0
+    - inventory_hostname == groups['svc-prx-openresty'][0]
   block:
     - name: "🔍 Check if the queued vhosts are reachable"
       uri_probe_batch:

roles/sys-stk-front-proxy/tasks/main.yml

@@ -55,6 +55,7 @@
       url: "{{ lookup('tls', front_proxy_domain, 'url.base') }}"
       status_codes: "{{ lookup('applications') | accepted_status_codes(front_proxy_application_id, lookup('tls', front_proxy_domain, 'domain')) }}"
   changed_when: false
+  when: IS_STACK_HOST | bool
 
 - name: 📂 Include dependencies
   include_role: