fix: make pytest collection coexist with ComfyUI root __init__

pytest collects the repo root as a Package and imports its __init__.py
during test setup; guard the ComfyUI-only relative imports behind
__package__ so the suite can import gates.* standalone. Drop the
tests/ package marker and pin pythonpath/testpaths.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

pyproject.toml

@@ -7,3 +7,12 @@ requires-python = ">=3.10"
 [tool.comfy]
 PublisherId = "ethanfel"
 DisplayName = "ComfyUI Datasete Gates"
+
+[tool.pytest.ini_options]
+# The repo-root __init__.py is required by ComfyUI but breaks pytest's default
+# "prepend" collection if tests/ is a package (pytest walks up the __init__.py
+# chain and tries to import the root package, whose relative imports fail
+# outside ComfyUI). Keeping tests/ a non-package dir avoids that; pythonpath
+# makes `gates` importable from the repo root.
+pythonpath = ["."]
+testpaths = ["tests"]