docs: Add missing XML documentation

[thomhurst]

Summary

• Add XML documentation for OperatingSystemVersion property in IEnvironmentContext
• Add parameter documentation for IBuildSystemDetector.Is method
• Complete parameter documentation for all IDownloader methods

Issues Closed

Closes #1643
Closes #1629
Closes #1609

🤖 Generated with Claude Code

[thomhurst]

Summary

This PR adds missing XML documentation for public API members in three interface files.

Critical Issues

None found ✅

Suggestions

The documentation improvements look good and complete. The parameter descriptions are clear and follow proper XML documentation conventions. The return value descriptions have been enhanced to be more specific and helpful.

One minor observation (not blocking):

• In IDownloader.cs:13, the return description says "The downloaded file" which accurately describes the return type now, much better than the previous generic description.
• In IDownloader.cs:21, the return description correctly notes the nullable return type: "The downloaded content as a string, or null if the download failed."
• In IEnvironmentContext.cs:22-24, the added documentation for OperatingSystemVersion is consistent with the style of other properties in the interface.
• In IBuildSystemDetector.cs:64-65, the parameter and return documentation are now complete and clear.

All changes follow standard XML documentation practices and improve API discoverability.

Previous Review Status

Unable to retrieve previous comments due to API token scope limitations, but the PR appears to be a straightforward documentation improvement.

Verdict

✅ APPROVE - No critical issues. This is a clean documentation improvement that enhances the public API surface.