a837b25d73
Adds the admin/diagnostics surface from SPEC §7.2: - doctor [--account]: per-account IMAP + (RW) SMTP connectivity/auth checks via new mail.CheckIMAP/CheckSMTP (connect+auth only, no mail). Exit non-zero on any failure; secrets never printed. - store.UpdateAccount: partial edit, re-encrypts password/secrets only when a non-empty value is supplied (blank keeps existing). RecentAuditFor(account). - config set/get (validates audit_retention_days), audit list [--account][--limit], account edit (flag partial-update) / remove [--yes]. - internal/tui: bubbletea AccountForm with pure, fully-tested Fields (validation + store.Account assembly + edit prefill). init / bare `account add` / `account edit --name X` drop into the TUI; flag forms remain for scripting. Built test-first; full suite green incl -race. Validated live against the mxlogin (password) and Gmail (app-password) accounts. Live validation caught a real bug: doctor authenticated with empty passwords because it iterated ListAccounts (which strips secrets) — fixed to re-fetch via GetAccount, locked in by a regression test. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>