test(hermes-plugin): check Windows installation

[ehz0ah]

Description

OpenViking's real Hermes plugin installation check runs only in the Ubuntu activation job. The Windows Quick Local job copies the plugin directly, so it cannot detect failures in hermes plugins install on a fresh destination. NousResearch/hermes-agent#139533 reported this exact Windows installer path.

This PR adds a Windows install-only smoke to the existing platform matrix. It uses the Hermes commit that fixed fresh-destination installation, runs the real installer, compares the installed plugin with the checked-out source, and uploads the installation evidence. Plugin activation remains in the existing POSIX job because it requires pty.

Human Involvement

• A human participated in the implementation or review loop
• This PR was generated entirely by AI agents without human participation in the loop

Related Issue

• plugins install crashes on Windows when the destination directory does not exist (FileNotFoundError in pm/filesystem.is_junction) NousResearch/hermes-agent#139533

Type of Change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update
• Refactoring (no functional changes)
• Performance improvement
• Test update

Changes Made

• Add an install-only mode to the existing real Hermes installation checker.
• Run that checker on Windows against Hermes fix commit bb706e92c775b6a16765b3249a6fdd0427e7430c.
• Upload the Windows installation log and evidence with the existing platform artifact.

Testing

• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• I have tested this on the following platforms:
  • Linux
  • macOS
  • Windows

Validated locally with:

• Two byte-identical isolated install-only runs with injected CRLF content, each passing 11 of 11 assertions.
• ruff 0.15.5 format --check scripts/check-hermes-plugin-install.py
• ruff 0.15.5 check scripts/check-hermes-plugin-install.py
• actionlint 1.7.7 .github/workflows/hermes-plugin-tests.yml
• python3 -m py_compile scripts/check-hermes-plugin-install.py
• git diff --check

mypy 1.19.1 scripts/check-hermes-plugin-install.py still reports the existing sys._base_executable attribute error on the unchanged activation path.

Checklist

• My code follows the project's coding style
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• Any dependent changes have been merged and published

Screenshots (if applicable)

Not applicable.

Additional Notes

The first Windows CI run completed the real installation and exposed a CRLF-sensitive byte comparison in the checker. The follow-up uses UTF-8 text equality. The Windows CI job remains the authoritative native-platform validation.