Add sort and order parameters to search_repositories tool

[kerobbi]

This PR adds explicit sort and order params to the search_repositories tool to align with other search_* tools.

Changes

• Added sort param with enum values: stars, forks, help-wanted-issues, updated
• Added order param with enum values: asc, desc

The parameters are accepted by the REST API endpoint, and should help with models confusion when it comes down to sorting.

[Copilot]

Pull Request Overview

This PR adds explicit sort and order parameters to the search_repositories tool to provide better control over search result ordering and align with other search tools in the codebase.

• Added sort parameter with enum values (stars, forks, help-wanted-issues, updated) to specify sorting criteria
• Added order parameter with enum values (asc, desc) to control sort direction
• Updated tests and documentation to reflect the new parameters

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

File	Description
pkg/github/search.go	Added sort and order parameter definitions and handling logic
pkg/github/search_test.go	Added test coverage for the new sort and order parameters
pkg/github/toolsnaps/search_repositories.snap	Updated schema snapshot to include new parameter definitions
README.md	Updated documentation to list the new optional parameters

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