Fix gitignore syntax compliance and improve file filtering logic

[yamadashy]

Changes

1. Fixed handling of .gitignore and .repopackignore files to properly comply with gitignore syntax
2. Migrated custom ignore pattern processing from gitignore syntax to glob patterns

Motivation

This change addresses a critical issue where our handling of .gitignore and .repopackignore files was not fully compliant with gitignore syntax. The updates improve the file filtering process by:

• Ensuring proper adherence to gitignore syntax rules

Notes

• This change may affect which files are included/excluded in the packed output. Users should review their ignore patterns to ensure desired behavior.