Update tests for tag removal

- Remove Tag/TagHistory model tests from unit tests
- Update CacheSettings tests to remove allow_public_internet field
- Replace tag= with version= in upload_test_file calls
- Update test assertions to use versions instead of tags
- Remove tests for tag: prefix downloads (now uses version:)
- Update dependency tests for version-only schema

backend/tests/factories.py

@@ -96,7 +96,6 @@ def upload_test_file(
     package: str,
     content: bytes,
     filename: str = "test.bin",
-    tag: Optional[str] = None,
     version: Optional[str] = None,
 ) -> dict:
     """
@@ -108,7 +107,6 @@ def upload_test_file(
         package: Package name
         content: File content as bytes
         filename: Original filename
-        tag: Optional tag to assign
         version: Optional version to assign
 
     Returns:
@@ -116,8 +114,6 @@ def upload_test_file(
     """
     files = {"file": (filename, io.BytesIO(content), "application/octet-stream")}
     data = {}
-    if tag:
-        data["tag"] = tag
     if version:
         data["version"] = version