Rename registry to inventory in comments

Update remaining references to 'registry' in code comments to use
'inventory' consistently after the package rename.

fix(get_file_contents): Restore correct implementation from #1582

The refactor incorrectly restructured the GetFileContents logic:
- Move 'if rawOpts.SHA != "" { ref = rawOpts.SHA }' before GetContents call
- Always call GetContents first (not conditionally based on path suffix)
- Restore matchFiles helper function for proper fallback handling
- Use matchFiles when Contents API fails or raw API fails

This aligns with the improvements from PR #1582 that was merged into main.

v0.26.0-rc.1: Registry pattern refactor

Pre-release candidate for the toolsets -> registry refactor.

Key changes:
- New registry package replacing toolsets package
- Self-describing tools with toolset metadata
- Builder pattern for registry configuration
- Deferred handler creation via HandlerFunc
- ForMCPRequest optimization for remote server
- Feature flag support in tool filtering

Fixes:
- Proper GitHub API error handling in gists.go for observability

Release v0.25.0

Release v0.25.0

fix: include empty properties in get_me schema for OpenAI compatibility

Release v0.24.0

Release v0.23.0

Prerelease for Go SDK v0.23.0

Release v0.22.0