fix(domain-filters): support dependency expansion via seed param

- Added missing 'Iterable' import in 'canonical_domains_map' to avoid NameError.
- Introduced 'seed' parameter so the filter can start traversal from current play apps
  while still emitting canonical domains for discovered dependencies (e.g. web-svc-collabora).
- Updated 01_constructor.yml to pass full 'applications' and a clean 'seed' list
  (using dict2items → key) instead of '.keys()' method calls, fixing integration
  test error: 'reference to application keys is invalid'.

This resolves issues where collabora domains were missing and integration tests failed.

Ref: https://chatgpt.com/share/68a51f9b-3924-800f-a41b-803d8dd10397

tasks/stages/01_constructor.yml

@@ -41,10 +41,16 @@
 
   - name: Merge current play domain definitions
     set_fact:
-      current_play_domains: >- 
-        {{  current_play_applications |
-            canonical_domains_map(PRIMARY_DOMAIN) | 
-            combine(domains | default({}, true), recursive=True) 
+      current_play_domains: >-
+        {{
+          applications
+          | canonical_domains_map(
+              PRIMARY_DOMAIN,
+              recursive=True,
+              roles_base_dir=([ playbook_dir, 'roles' ] | path_join),
+              seed=(current_play_applications | dict2items | map(attribute='key') | list)
+            )
+          | combine(domains | default({}, true), recursive=True)
         }}
   
   - name: Merge domain definitions for all domains