Summary

gog calendar events --from/--to accept relative date expressions (today, tomorrow,
monday, now, plain dates), but gog calendar freebusy --from/--to are forwarded raw to the
API and require RFC3339, so the same expressions fail. Inconsistent and surprising.

Repro

gog calendar events   --from today --to tomorrow   # works
gog calendar freebusy --from today --to tomorrow   # fails (API rejects "today")

Root cause (v0.22.0, 197992a)

• events resolves --from/--to via the shared parser timeparse.ParseRangeExpr
  (internal/cmd/time_helpers.go:257); flags documented as "RFC3339 with timezone, date, or
  relative: now, today, tomorrow, monday" (docs/commands/gog-calendar-events.md:37,54).
• freebusy passes raw strings straight through: TimeMin: c.From / TimeMax: c.To
  (internal/cmd/calendar_freebusy.go:38-39); help says "RFC3339, required" (:19-20).

Suggested fix

Route freebusy --from/--to through the same ParseRangeExpr helper as events (resolving in
the calendar's timezone), and update the flag help. Recommend auditing other date-taking calendar
commands (e.g. conflicts) for the same gap.

Environment

gog v0.22.0 (confirmed by reading source at 197992a).