Add a Monday-default --week-start option for every weekday and carry it through domain layout, full and compact rendering, event query windows, print mode, and the interactive TUI.
Preserve byte-compatible Monday output and cover rotated headers, spill dates, invalid input, sanitizer behavior, and live terminal restoration.
Derive session calendars from event metadata and apply one visibility contract to month rendering, appointment focus, and search without filtering persistence writes.
Add keyboard picker coverage, full-model save regression tests, documentation, warning-clean builds, sanitizer verification, and live PTY terminal restoration checks.
