Closes #1: Implement ABNF-compatible RFC 5322 email address parser covering sections 3.2-4.4

[misakaAron]

Summary

Implements a comprehensive ABNF-compatible Python email address parser based on RFC 5322, covering all relevant sections (3.2 through 4.4).

What's included

• Full ABNF compliance for modern generating syntax and obsolete interpreting syntax
• 149 passing tests covering all major productions: quoted-pair, FWS/CFWS, atom/dot-atom, quoted-string, word/phrase, date-time, addr-spec, mailbox/group, address-list, plus all obsolete variants
• Edge case handling: CFWS in dates, comments in domains, quoted local-parts, domain literals, source routes, obs-phrase with periods, multi-line obsolete FWS

Files

• parser.py — Main parser implementation with RFC5322Parser class and convenience functions
• est_parser.py — Comprehensive test suite (149 tests, 100% pass)