perf(prepull): pull the Playwright image in the background on hosts that run E2E

The E2E stage pulled mcr.microsoft.com/playwright synchronously right before the tests, 11-19 min on every reinstall and on every fresh CI runner, because the background pre-pull only knew the app images. The constructor now hands the runner image to the pre-pull when RUNTIME runs E2E and the host has a server stage, the only stage that runs test-e2e-playwright; a backup-only host would otherwise install Docker for an image it never uses. Measured on a compose reinstall: the pull before the tests drops from 18m49s to 1.6s.

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

roles/sys-svc-container/tasks/utils/prepull/start.yml

@@ -1,4 +1,7 @@
 ---
+# REQUIRED:
+#   sys_svc_container_prepull_extra  # image references to pull besides the app images of the deploy, e.g. the E2E runner
+
 - name: "📥 Pre-pull the images of this deploy in the background"
   when:
     - not (STORAGE_CONSTRAINED | bool)
@@ -8,10 +11,9 @@
     - name: "🧮 Derive the images the deploy of the host runs"
       ansible.builtin.set_fact:
         sys_svc_container_prepull_plan: >-
-          {{
-            lookup('applications')
-            | update_pull_images(lookup('application_closure', group_names | intersect(lookup('deployment').running)))
-          }}
+          {%- set plan = lookup('applications')
+                         | update_pull_images(lookup('application_closure', group_names | intersect(lookup('deployment').running))) -%}
+          {{ plan | combine({'pull': plan.pull + (sys_svc_container_prepull_extra | reject('in', plan.pull) | list)}) }}
 
     - name: "📥 Pull the images the host does not hold yet"
       ansible.builtin.include_tasks: "{{ role_path }}/tasks/utils/prepull/pull.yml"

tasks/stages/01_constructor.yml

@@ -224,6 +224,10 @@
   ansible.builtin.include_role:
     name: sys-svc-container
     tasks_from: utils/prepull/start.yml
+  vars:
+    sys_svc_container_prepull_extra: >-
+      {{ [lookup('config', 'test-e2e-playwright', 'services.playwright.image') ~ ':' ~ lookup('config', 'test-e2e-playwright', 'services.playwright.version')]
+         if RUNTIME in ['dev', 'act', 'github'] and 'server' in (group_names | get_deployment_types_from_groups) else [] }}
 
 - name: 🛠️ Preload shared services
   ansible.builtin.include_role: