feat: add macOS and Linux support for browser cookie extraction

[Jatin-Shihora]

The browser cookie extraction currently only works on Windows. macOS and Linux users are forced to use manual cookie entry, which requires opening DevTools, finding the cookies tab, and copy-pasting two values. This is the biggest friction point for non-Windows users.

What should happen
Extend browser_cookies.py to support Chrome/Edge/Brave cookie extraction on macOS and Linux.

Things to consider

• Cookie storage locations differ per OS:
  • macOS: ~/Library/Application Support/Google/Chrome/Default/Cookies (SQLite, encrypted with Keychain)
  • Linux: ~/.config/google-chrome/Default/Cookies (SQLite, encrypted with GNOME Keyring or KWallet)
• macOS encryption uses the system Keychain. You'll need security find-generic-password or the keyring Python package to get the decryption key
• Linux encryption uses PBKDF2 with a key from the system keyring (GNOME Keyring, KWallet, or a hardcoded fallback key)
• The current Windows implementation uses Chrome DevTools Protocol (CDP) to grab cookies from a running browser. This approach also works on macOS/Linux and might be simpler than dealing with encrypted SQLite databases
• Test on actual macOS and Linux machines. Cookie formats and encryption change between browser versions
• Consider adding this as a separate module per platform to keep the code organized

Note: I have tested things out in windows. So support from other OS users will help a lot to make sure things are proper in Mac and Linux!