Adds the second F2 sub-project on top of the merged IMAP core: full SEARCH criteria matching (flags, dates, size, headers, body/text, NOT/OR), EXPUNGE (soft-delete via expunged_at), COPY, and MOVE (RFC 6851, advertised via CapMove/CapUIDPlus). Verified end-to-end with a real go-imap/v2 client against embedded Postgres. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>