feat: enhance .cgrignore to support glob patterns

[jxstanford]

Summary

The current .cgrignore implementation supports exact directory name matches. This issue proposes enhancing it to support more .gitignore-like features.

Proposed Enhancements

• Glob patterns (*.log, **/*.pyc)
• Path patterns (foo/bar/baz)
• Negation patterns (!important_vendor)
• Directory-only patterns (dir/)

Current Behavior

# .cgrignore - exact directory name matches only
vendor      # matches any directory named "vendor"
.cache      # matches any directory named ".cache"

Proposed Behavior

# .cgrignore - with glob support
*.log           # match files ending in .log
**/__pycache__  # match __pycache__ at any depth
build/          # match only directories named build
!important/     # negation - don't ignore this one

Related

• PR feat: add .cgrignore file support for custom exclude patterns #219 implements the basic .cgrignore support