Add read tools (get_mail, read_mail, get_calendar) and guarded write tools (send_mail, set_mail_read, respond_calendar_event). Writes resolve an explicit character, return a dry-run preview unless confirm=true, and only execute when writes are enabled. Add EsiClient put/delete. Closes #23, #24. 112 tests, coverage 90%. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
