Containers had no TZ set, so any time-aware code inside ran in UTC while
the host interpreted bare timestamps as local time. Now TIMEZONE from
config.ts is passed via -e TZ= to the container args.
Also rejects Z-suffixed or offset-suffixed timestamps in the container's
schedule_task validation, since bare timestamps are expected to be local
time and silently accepting UTC suffixes would cause an offset mismatch.
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>