feat: add Windows setup script and launcher

[hongquanli]

Stacked on #622. Base is feat/pyqt6-napari07-migration-v2, not master — see Why this can't target master. Retarget once #622 lands.

Problem

There is no reproducible way to install this software on Windows.

• setup_22.04.sh is Ubuntu-only: apt, udev rules, dialout, apt-mark, bundled .run camera installers.
• The forum post the README links for Windows predates the PyQt6 work — it installs Python 3.10, PyQt5 and napari 0.5.6, so following it today produces an environment PyQt6 / napari 0.7 migration + review fixes (continuation of #606) #622's code cannot run in.

What this adds

setup_windows.ps1 — the counterpart of setup_22.04.sh. Installs Git + Python 3.12 via winget, clones recursively, builds a virtualenv with the same pinned PyQt6 6.11 / napari 0.7.1 stack, seeds machine_configs, and writes Desktop shortcuts. Steps with no Windows equivalent are dropped; camera drivers are vendor installers, so the script reports what remains rather than installing it.

main_hcs.bat — the launcher the shortcuts point at.

.gitattributes — two lines pinning *.bat/*.ps1 to eol=crlf. The repo had none, and cmd.exe can misparse a multi-line if errorlevel 1 ( ... ) block in a .bat stored with LF — a failure that presents as a syntax error rather than a line-ending problem.

Deliberate differences from the Ubuntu script

• A virtualenv, not a system-wide pip install. Windows has no distro Python to protect, and an isolated env is the only way to guarantee exactly one Qt binding — which napari/vispy OpenGL rendering requires.
• PATH is re-read from the registry after winget. Installers update the registry, not the running process. Without the refresh git.exe is still missing — and control/utils.py imports GitPython at module scope, which raises ImportError with no git executable. That makes git a hard runtime requirement, not just an installer one.
• It refuses to guess a configuration*.ini. _def.py globs that pattern and silently takes the first match, so the script reports when zero or several are present and lists the candidates. It does seed illumination_channel_config.yaml from the example (its absence degrades the GUI and fails ~13 tests) but warns loudly that the laser lines must be checked.

Why this can't target master

setup_windows.ps1 installs PyQt6 6.11 + napari 0.7.1. On master that produces an environment the code cannot run in — master still sets QT_API = "pyqt5" and uses four APIs that don't exist in PyQt6:

gui_hcs.py:1441:  desktop_info = QDesktopWidget()
gui_hcs.py:2488:  if isinstance(format_, QVariant):
widgets.py:4461:  self.dropdown_modeSelection.activated[str].connect(...)
core.py:1686:     if isinstance(sample_format, QVariant):

These are the exact APIs #622 fixes. They sit inside functions, so the modules import fine and the GUI then fails during construction — and because qtpy falls back from a missing binding with only a warning (Selected binding 'pyqt5' could not be found; falling back to 'pyqt6'), the resulting failure is confusing to diagnose. So this belongs on top of #622.

Verification

On Windows 11 x64, run against an existing checkout to confirm idempotency:

==> Verifying the environment
No broken requirements found.
  qtpy binding : PyQt6
  Qt           : 6.11.0
  napari       : 0.7.1
  numpy        : 2.5.2
  opencv       : 5.0.0

Re-running reuses the venv, leaves an existing illumination_channel_config.yaml alone, detects the single configuration*.ini, and exits 0. main_hcs.bat --simulation brings up the GUI.

Full suite on this branch: 1634 passed, 0 failed, 12 skipped.

Note on scope

This makes Windows a supported platform, which is a policy question as much as a technical one — the README currently says Ubuntu 22.04 is the most tested platform and says nothing about Windows beyond the forum link. Happy to add a README section pointing at this script if you want it discoverable, or to leave it undocumented as a best-effort path.