* feat(cli): show cached update notices after commands
* docs(cli): describe update notices
* fix(cli): type update check environment
* fix(cli): decouple update notice display from refresh and harden suppression
Display a cached "update available" notice based solely on the lastNoticeAt
24h throttle, independent of checkedAt refresh freshness, matching the design's
independent display/refresh decisions. Suppress the check unconditionally under
--json, CI, and non-TTY before consulting output-mode preferences, so a
KTX_OUTPUT=pretty override can no longer make CI/non-TTY contexts phone npm.
