Fix search_files_by_name to properly handle glob patterns with **

[codegen-sh]

Description

This PR fixes an issue with the search_files_by_name tool where it wasn't properly handling glob patterns that include ** (recursive directory matching), such as **/.github/workflows/*.yml.

Changes

1. Improved handling of glob patterns with ** for both fd and find commands
2. Added specific handling for patterns that start with **/
3. For find, using -path instead of -name when the pattern contains **
4. For fd, added the -t f flag to ensure we're only finding files
5. Added filtering to remove empty strings from results
6. Updated documentation to include example with **/.github/workflows/*.yml

Testing

This change should allow patterns like **/.github/workflows/*.yml to correctly find GitHub workflow files at any directory depth.

Fixes the issue reported in Slack where search_files_by_name wasn't finding GitHub workflow files with the pattern **/.github/workflows/*.yml.