docs: Add XML documentation to installer interfaces (#1551)

[thomhurst]

Summary

• Add comprehensive XML documentation to all installer interfaces
• Document interface purpose, method parameters, and return values

Changes

Added documentation to:

• IFileInstaller: Methods for installing from local files or web URLs
• ILinuxInstaller: Methods for installing on Linux systems (dpkg)
• IWindowsInstaller: Methods for installing on Windows (MSI, EXE)
• IMacInstaller: Methods for installing on macOS (Homebrew)

Why This Change

These are public APIs that users interact with for installing software. Clear documentation helps users understand how to use these interfaces correctly.

Fixes #1551

Test plan

• Build succeeds locally
• CI builds pass

🤖 Generated with Claude Code

[thomhurst]

Summary

This PR adds comprehensive XML documentation to four installer interface files (IFileInstaller, ILinuxInstaller, IWindowsInstaller, IMacInstaller).

Critical Issues

None found ✅

Suggestions

Minor consistency issue in ILinuxInstaller:
The InstallFromDpkg method is missing a CancellationToken parameter while IFileInstaller methods include it. For consistency across the codebase and to allow cancellation of long-running installation operations, consider adding:

Task<CommandResult> InstallFromDpkg(DpkgInstallOptions options, CancellationToken cancellationToken = default);

Similarly for IMacInstaller.InstallFromBrew and both IWindowsInstaller methods - they should all support cancellation tokens for consistency.

However, this would be a breaking API change if implementations don't already support it, so it's better addressed in a separate PR if desired.

Verdict

✅ APPROVE - No critical issues. The documentation is clear, accurate, and follows standard XML doc conventions. This improves the developer experience for users of these public APIs.

[Copilot]

Pull request overview

This PR adds comprehensive XML documentation to four installer interfaces in the ModularPipelines framework, improving API discoverability and usability for developers.

• Adds interface-level and method-level XML documentation comments
• Documents all parameters and return values with clear descriptions
• Provides context on each installer's platform-specific functionality

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
src/ModularPipelines/Context/IFileInstaller.cs	Adds documentation for cross-platform file and web-based installation methods
src/ModularPipelines/Context/ILinuxInstaller.cs	Adds documentation for Linux dpkg package installation
src/ModularPipelines/Context/IMacInstaller.cs	Adds documentation for macOS Homebrew installation
src/ModularPipelines/Context/IWindowsInstaller.cs	Adds documentation for Windows MSI and EXE installer methods