agenda --today uses UTC for day boundaries, wrong results in non-UTC timezones

[maximalmargin]

Bug

gws calendar +agenda --today uses UTC to determine day boundaries, so after ~4pm PST (midnight UTC), "today" returns tomorrow's events instead.

Repro

System timezone: PST (America/Los_Angeles)
System time: Thu Mar 5 20:20 PST 2026

$ gws calendar +agenda --today --calendar my-calendar@gmail.com
# Returns Mar 6 event (tomorrow), not Mar 5 (today)

$ gws calendar +agenda --tomorrow --calendar my-calendar@gmail.com
# Returns Mar 7 event (day after tomorrow)

The event timestamps in the output correctly show -08:00 (PST), but the day boundary calculation uses UTC.

Expected

--today, --tomorrow, and --days N should respect the system's local timezone (or the calendar's configured timezone) when computing which day it is.

Workaround

Using --days 2 and manually filtering results to the actual local date.

Environment

• @googleworkspace/cli v0.4.1
• macOS (Darwin 24.6.0)
• Timezone: America/Los_Angeles (PST, UTC-8)

[jpoehnelt]

Could also consider using APIs to get user timezone instead of machine timezone.

[jpoehnelt]

Pull request?