Fix Windows CI: add Mesa software OpenGL for headless napari tests

[Copilot]

The build (3.13, windows-latest) deploy job fails because napari/vispy calls glGetIntegerv(GL_MAX_TEXTURE_SIZE) during Viewer initialization, but GitHub Actions Windows runners have no GPU, so no OpenGL context exists and PyOpenGL raises GL_INVALID_OPERATION (error 1282). The prior NAPARI_TESTING=1 fix was insufficient — it sets napari's test mode but doesn't provide an OpenGL implementation.

Changes

• .github/workflows/deploy.yml: Add ssciwr/setup-mesa-opengl@v1 as a Windows-only step before tests run. This installs Mesa3D's CPU-based opengl32.dll on the runner, giving napari/vispy a valid software OpenGL context to initialize against.

- name: Setup Mesa OpenGL for headless rendering (Windows only)
  if: runner.os == 'Windows'
  uses: ssciwr/setup-mesa-opengl@v1

[deepsource-io]

DeepSource Code Review

We reviewed changes in ed5d10b...fd650e2 on this pull request. Below is the summary for the review, and you can see the individual issues we found as inline review comments.

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PR Report Card

Overall Grade

Security   Reliability   Complexity   Hygiene   Coverage

Code Review Summary

Analyzer	Status	Updated (UTC)	Details
Python		Aug 13, 2026 1:15a.m.	Review ↗
Code coverage		Aug 13, 2026 1:22a.m.	Review ↗

Code Coverage Summary

Language	Line Coverage (Overall)
Aggregate	100%
Python	100%

➟ Additional coverage metrics may have been reported. See full coverage report ↗

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