* Enhance search functionality with new query filters and utility functions- Added multiple test cases for searching issues with various query filters in `issues_test.go`.- Introduced utility functions in `search_utils.go` to check for specific filters and extract repository information from queries.- Created comprehensive tests in `search_utils_test.go` to validate the new filtering logic and ensure accurate query parsing.* Refactor repository filter extraction in search utilities- Renamed `extractRepoFilter` to `hasRepoFilter` to simplify the function's purpose.- Updated test cases in `search_utils_test.go` to reflect the new function name and logic.- Adjusted tests to focus on the presence of the `repo:` filter rather than extracting owner and repo details.* Enhance search functionality with additional query filters and utility functions- Added new test cases for searching pull requests and users with various query filters in `pullrequests_test.go` and `search_test.go`.- Implemented a utility function `hasTypeFilter` in `search_utils.go` to check for the presence of `type:` filters in queries.- Updated the search handler to conditionally prepend the `type:` filter based on the presence of existing filters, improving query handling.* Updated both regex patterns to handle this edge case<!--    Thank you for contributing to GitHub MCP Server!    Please reference an existing issue: `Closes #NUMBER`    Screenshots or videos of changed behavior is incredibly helpful and always appreciated.    Consider addressing the following:    - Tradeoffs: List tradeoffs you made to take on or pay down tech debt.    - Alternatives: Describe alternative approaches you considered and why you discarded them.-->Closes: