Support for --hidden and --no-ignore Options

[brummelte]

Feature Request: --hidden, --no-ignore

Add a --hidden flag to let code2prompt include hidden directories (e.g. .git, .config). By default, these seem to remain ignored, but with --hidden, any dot-folder could be scanned.

This is separate from .gitignore handling — currently code2prompt respects .gitignore patterns by default — so a --no-ignore option could skip that.