feat(logout): wire injector to web-svc-logout and add robust CORS/CSP for /logout

- sys-front-inj-logout: depend on web-svc-logout (run-once guarded) and simplify task flow.
- web-svc-logout: align feature flags/formatting and extend CSP:
  - add cdn.jsdelivr.net to connect/script/style and quote values.
- Nginx: move CORS config into logout-proxy.conf.j2 with dynamic vars:
  - Access-Control-Allow-Origin set to canonical logout origin,
  - Allow-Credentials=true,
  - Allow-Methods=GET, OPTIONS,
  - basic headers list (Accept, Authorization),
  - cache disabled for /logout responses.
- Drop obsolete CORS var passing from 01_core.yml; headers now templated at proxy layer.

Prepares clean cross-origin logout orchestration from https://logout.veen.world.

Refs: ChatGPT discussion – https://chatgpt.com/share/68ebb75f-0170-800f-93c5-e5cb438b8ed4

roles/web-svc-logout/config/main.yml

@@ -1,9 +1,9 @@
 features:
-  matomo:           true
-  css:              true
-  desktop:  true
-  javascript:       false
-  logout:           false
+  matomo:     true
+  css:        true
+  desktop:    true
+  javascript: false
+  logout:     false
 server:
   domains:
     canonical:
@@ -19,10 +19,11 @@ server:
       connect-src:
         - "{{ WEB_PROTOCOL }}://*.{{ PRIMARY_DOMAIN }}"
         - "{{ WEB_PROTOCOL }}://{{ PRIMARY_DOMAIN }}"
+        - "https://cdn.jsdelivr.net"
       script-src-elem:
-        - https://cdn.jsdelivr.net
+        - "https://cdn.jsdelivr.net"
       style-src-elem:
-        - https://cdn.jsdelivr.net
+        - "https://cdn.jsdelivr.net"
       frame-ancestors:
         - "{{ WEB_PROTOCOL }}://<< defaults_applications[web-app-keycloak].server.domains.canonical[0] >>"