Fix tests for tag removal and version behavior

- Fix upload response to return actual version (not requested version)
  when artifact already has a version in the package
- Update ref_count tests to use multiple packages (one version per
  artifact per package design constraint)
- Remove allow_public_internet references from upstream caching tests
- Update consistency check test to not assert global system health
- Add versions field to artifact schemas
- Fix dependencies resolution to handle removed tag constraint

backend/tests/integration/test_packages_api.py

@@ -234,7 +234,11 @@ class TestPackageCascadeDelete:
     def test_ref_count_decrements_on_package_delete(
         self, integration_client, unique_test_id
     ):
-        """Test ref_count decrements for all tags when package is deleted."""
+        """Test ref_count decrements when package is deleted.
+
+        Each package can only have one version per artifact (same content = same version).
+        This test verifies that deleting a package decrements the artifact's ref_count.
+        """
         project_name = f"cascade-pkg-{unique_test_id}"
         package_name = f"test-pkg-{unique_test_id}"
 
@@ -256,23 +260,17 @@ class TestPackageCascadeDelete:
         )
         assert response.status_code == 200
 
-        # Upload content with multiple tags
+        # Upload content with version
         content = f"cascade delete test {unique_test_id}".encode()
         expected_hash = compute_sha256(content)
 
         upload_test_file(
-            integration_client, project_name, package_name, content, version="v1"
-        )
-        upload_test_file(
-            integration_client, project_name, package_name, content, version="v2"
-        )
-        upload_test_file(
-            integration_client, project_name, package_name, content, version="v3"
+            integration_client, project_name, package_name, content, version="1.0.0"
         )
 
-        # Verify ref_count is 3
+        # Verify ref_count is 1
         response = integration_client.get(f"/api/v1/artifact/{expected_hash}")
-        assert response.json()["ref_count"] == 3
+        assert response.json()["ref_count"] == 1
 
         # Delete the package
         delete_response = integration_client.delete(