Don’t output hidden files

[sobeaa]

code-slicer should ignore hidden files by default.

Hidden should include:

• files and folders starting with .
• Windows hidden files, if practical to detect reliably

Examples:

• .env
• .gitignore
• .github/
• .config/

Expected behavior:

• hidden files should not be included in output by default
• hidden folders should not be traversed by default
• explicitly passed entry files should still work, even if hidden

Open question:

Should explicitly imported hidden files be included, warned about, or skipped?