TDD task-by-task plan for the read-only emcli: crypto, encrypted store,
seen-set read state, policy filtering, IMAP read, and the agent
list/get/search/ack commands with flag-based admin. Phases 2-4 (send,
OAuth2, TUI) to follow as their own plans.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
