Update README for truststore-based architecture

Completely revises the README to accurately reflect the new truststore
integration instead of the old monkey-patching approach.

Key updates:
- Explain truststore integration vs monkey-patching
- Add Python 3.10+ and truststore requirements
- Document native OS integration (Security framework, CryptoAPI, OpenSSL)
- Note compatibility with all SSL libraries (requests, urllib3, httpx, etc.)
- Update PyInstaller instructions for inject_truststore() function
- Add Architecture section explaining bootstrap process
- Credit truststore library and Seth Michael Larson
- Emphasize reliability improvements over patching approach

The documentation now properly represents the modern, robust implementation
while maintaining clear installation and usage instructions.

🤖 Generated with [Claude Code](https://claude.ai/code

)

Co-Authored-By: Claude <noreply@anthropic.com>