Compiled files not copied to wheel

[QuasarX1]

When explicitly using 0.6.0rc0, I am able to target .pyx files for compilation and they are in fact compiled, but the .pyx files are not copied into the wheel when running hatch build.

I'm working with a very simple test project, so here is the outline:
src/test_cython/

• init.py
• about.py
• example.pyi
• example.pyx

__init__.py

from .example import cython_hello

example.pyx

def cython_hello():
    print("Hello from Cython!")

On running hatch build two more files are created:

• example.c
• example.cp312-win_amd64.pyd

The C source file gets copied to the wheel without issue, but the .pyd does not.

Here is the end of the output from hatch build:

Finished generating code
copying <user-folder>\AppData\Local\Temp\tmp1fzb7f_k\build\test_cython\example.cp312-win_amd64.pyd -> src\test_cython

Post-build artifacts
['./src/test_cython\\__pycache__\\', './src/test_cython\\__pycache__\\__init__.cpython-312.pyc']
./src/test_cython/**/*.pyx globbed ['./src/test_cython\\example.pyx']
./src/test_cython/*.cc globbed []
./src/test_cython/**/*.cc globbed []
./src/test_cython/**/*.py globbed ['./src/test_cython\\__about__.py', './src/test_cython\\__init__.py']
./src/test_cython/**/*.c globbed ['./src/test_cython\\example.c']
./src/test_cython/*.pxd globbed []
./src/test_cython/*.pyx globbed ['./src/test_cython\\example.pyx']
./src/test_cython/**/*.cpp globbed []
./src/test_cython/*.cpp globbed []
./src/test_cython/*.py globbed ['./src/test_cython\\__about__.py', './src/test_cython\\__init__.py']
./src/test_cython/**/*.pxd globbed []
./src/test_cython/*.c globbed ['./src/test_cython\\example.c']
Extensions complete
dist\test_cython-0.0.1-cp312-cp312-win_amd64.whl

What I think are the relevant parts from pyproject.toml (I'm not using a separate hatch.toml):

[build-system]
requires = ["hatchling", "cython", "hatch-cython==0.6.0rc0"]
build-backend = "hatchling.build"

...

[tool.hatch.build.targets.wheel.hooks.cython]
dependencies = ["hatch-cython"]
include-patterns = [
    "**/*.pyd"
]

[tool.hatch.build.targets.wheel.hooks.cython.options]
# include .h or .cpp directories
includes = []
# include numpy headers
include_numpy = false
include_pyarrow = false
parallel = false
src = "test_cython"

compile_args = [
  # single string
  "-v",
]

directives = { boundscheck = false, nonecheck = false, language_level = 3, binding = true }

compile_kwargs = { }

[tool.hatch.build.targets.wheel.hooks.cython.options.files]
targets = [
  "**/*.pyx"
]

...

Apologies if this is just me not understanding how to use the tool correctly or if I have missed something obvious! As I can get this working in an earlier version (all be it with all .py files getting arbitrarily compiled) I wandered if this could be an actual bug. I can provide the entire Hatch project on request as its only a small set of test code.