feat(campaign): complete reusable template workflow

tests/test_campaign_content_library.py

@@ -3,7 +3,10 @@ from __future__ import annotations
 from datetime import UTC, datetime
 
 from govoplan_campaign.backend.integrations import TemplatesCampaignIntegration
-from govoplan_campaign.backend.routes.campaigns import _campaign_content_library_item
+from govoplan_campaign.backend.routes.campaigns import (
+    _campaign_content_library_item,
+    _campaign_content_required_fields,
+)
 from govoplan_campaign.backend.schemas import CampaignContentLibrarySaveRequest
 from govoplan_core.core.templates import (
     TemplateContentDraftRequest,
@@ -109,6 +112,26 @@ def test_campaign_content_payload_keeps_revision_and_declared_target() -> None:
     assert payload["text"] == "Mit freundlichen Grussen"
     assert payload["published"] is True
     assert payload["revision"] == 3
+    assert payload["required_fields"] == []
+
+
+def test_campaign_content_required_fields_are_normalized_and_deduplicated() -> None:
+    payload = CampaignContentLibrarySaveRequest(
+        name="Greeting",
+        kind="campaign_part",
+        subject="Hello {{ local:display_name }}",
+        text="Reference ${global.case_reference}; hello {{local::display_name}}",
+        html="<p>{{fields.salutation}} {{local:to[2].email}} {{unsupported namespace}}</p>",
+    )
+
+    requirements = _campaign_content_required_fields(payload)
+
+    assert [item.path for item in requirements] == [
+        "global.case_reference",
+        "local.display_name",
+        "local.to.2.email",
+        "salutation",
+    ]
 
 
 def test_content_save_request_rejects_empty_selected_fragment() -> None: