readme: full rewrite for v0.4.x (UI + launchers, sharper structure)

- Top-of-page anchor is راهنمای فارسی (not URL-encoded)
- Document the launcher scripts as the recommended first run
- Update CA path (user-data dir, not ./ca)
- Mirror the English and Persian sections feature-for-feature
- Add a short security posture section
- Wrap the Persian block in <div dir=rtl> for correct rendering

Author: therealaleph