Fix Gitea issue label payloads

tests/test_gitea_backend.py

@@ -6,8 +6,10 @@ These tests ensure the Gitea backend works correctly with the API.
 
 import pytest
 import json
+from datetime import datetime, timezone
 from unittest.mock import Mock, patch, MagicMock
 from issue_core.backends.gitea.backend import GiteaBackend, GiteaAPIError
+from issue_core.core.models import Issue, IssueState, Label
 
 
 class TestGiteaBackend:
@@ -96,6 +98,29 @@ class TestGiteaBackend:
             called_url = mock_request.call_args[1]['url'] if 'url' in mock_request.call_args[1] else mock_request.call_args[0][1]
             assert called_url == 'https://git.example.com/api/v1/repos/owner/repo'
 
+    def test_gitea_payload_omits_name_only_labels(self):
+        """Gitea issue payloads only include numeric label IDs."""
+        now = datetime.now(timezone.utc)
+        issue = Issue(
+            id="",
+            number=0,
+            title="Test issue",
+            description="Test description",
+            state=IssueState.OPEN,
+            created_at=now,
+            updated_at=now,
+            labels=[
+                Label(name="priority:low"),
+                Label(name="source:rule", backend_id="not-a-number"),
+                Label(name="existing", backend_id="42"),
+            ],
+        )
+
+        payload = self.backend._unified_issue_to_gitea(issue)
+
+        assert payload["labels"] == [42]
+        assert payload["title"] == "Test issue"
+
     @patch('issue_core.backends.gitea.backend.requests.Session')
     def test_test_connection_success(self, mock_session_class):
         """Test test_connection method works correctly."""