refactor: improve service handling and introduce MODE_ASSERT

- Improved get_service_name filter plugin (clearer suffix handling, consistent var names).
- Added MODE_ASSERT flag to optionally execute validation/assertion tasks.
- Fixed systemd unit handling: consistent use of %I instead of %i, correct escaping of instance names.
- Unified on_failure behavior and alarm composer scripts.
- Cleaned up redundant logging, handlers, and debug config.
- Strengthened sys-service template resolution with assert (only active when MODE_ASSERT).
- Simplified timer and suffix handling with get_service_name filter.
- Hardened sensitive tasks with no_log.
- Added conditional asserts across roles (Keycloak, DNS, Mailu, Discourse, etc.).

These changes improve consistency, safety, and validation across the automation stack.

Conversation: https://chatgpt.com/share/68a4ae28-483c-800f-b2f7-f64c7124c274

roles/web-app-keycloak/tasks/05_rbac_client_scope.yml

@@ -46,6 +46,7 @@
       - scope_id_rbac | length > 0
       - (app_client_id_cmd.stdout | trim) is match('^[0-9a-f-]+$')
     fail_msg: "Could not determine client or scope ID."
+  when: MODE_ASSERT | bool
 
 - name: Get current optional client scopes
   shell: >