fix(sys-stk-backend): register the compose handlers before any role notifies them

sys-svc-rdbms notifies compose-up from dedicated.yml, but sys-svc-compose, the only role that owns that topic, was included after it. With ERROR_ON_MISSING_HANDLER on, the strategy raises before the task result is emitted, so the play dies with '[ERROR]: The requested handler compose-up was not found' and no PLAY RECAP. Rounds that happened to deploy another compose consumer first masked it; a round that deploys the app alone does not.

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

roles/sys-stk-backend/tasks/main.yml

@@ -18,6 +18,13 @@
       - "sso_proxy_enabled={{ lookup('sso', application_id, 'is_proxy_gated') }}"
   when: MODE_DEBUG | bool
 
+- name: "🧩 For '{{ application_id }}': Load sys-svc-compose"
+  include_role:
+    name: sys-svc-compose
+  vars:
+    compose_handlers_flush: false
+    database_consumer_id: "{{ _sys_stk_backend_database_consumer_id }}"
+
 - name: "🧩 For '{{ application_id }}': Load central RDBMS"
   include_role:
     name: sys-svc-rdbms
@@ -44,13 +51,6 @@
   vars:
     engine_consumer_id: "{{ application_id }}"
 
-- name: "🧩 For '{{ application_id }}': Load sys-svc-compose"
-  include_role:
-    name: sys-svc-compose
-  vars:
-    compose_handlers_flush: false
-    database_consumer_id: "{{ _sys_stk_backend_database_consumer_id }}"
-
 - block:
     - name: "🔧 set sso_proxy_application_id (needed due to lazy-loading issue)"
       set_fact:

tests/unit/python/roles/sys-stk-backend/test_handler_registration_order.py

@@ -0,0 +1,52 @@
+"""A role may only notify a handler topic that is already registered."""
+
+from __future__ import annotations
+
+import re
+import unittest
+
+from utils.cache.files import PROJECT_ROOT, iter_project_files_with_content, read_text
+from utils.cache.yaml import load_yaml_str
+from utils.roles.mapping import ROLE_FILE_TASKS_MAIN
+
+BACKEND = PROJECT_ROOT / "roles/sys-stk-backend" / ROLE_FILE_TASKS_MAIN
+COMPOSE_OWNER = "sys-svc-compose"
+_NOTIFY = re.compile(r"^\s*notify:\s*(?:\[\s*)?['\"]?(compose-[\w-]+)", re.MULTILINE)
+
+
+def _included_roles(tasks: list) -> list[str]:
+    names = []
+    for task in tasks:
+        include = task.get("include_role") or task.get("import_role") or {}
+        if isinstance(include, dict) and include.get("name"):
+            names.append(include["name"])
+    return names
+
+
+class TestHandlerRegistrationOrder(unittest.TestCase):
+    def test_the_backend_loads_the_handler_owner_before_any_other_role(self) -> None:
+        order = _included_roles(load_yaml_str(read_text(str(BACKEND))))
+        self.assertIn(COMPOSE_OWNER, order)
+        self.assertEqual(order[0], COMPOSE_OWNER)
+
+    def test_the_owner_still_holds_every_compose_topic_that_is_notified(self) -> None:
+        owner = ""
+        for path, content in iter_project_files_with_content(
+            extensions=(".yml",), exclude_tests=True
+        ):
+            if f"roles/{COMPOSE_OWNER}/handlers/" in path:
+                owner += content
+        notified = set()
+        for path, content in iter_project_files_with_content(
+            extensions=(".yml",), exclude_tests=True
+        ):
+            if "/roles/" in path:
+                notified.update(_NOTIFY.findall(content))
+        self.assertTrue(notified)
+        for topic in sorted(notified):
+            with self.subTest(topic=topic):
+                self.assertIn(topic, owner)
+
+
+if __name__ == "__main__":
+    unittest.main()