Use this when you need to convert a wall-clock date-time between IANA time zones with correct DST handling.

Use this when you need to convert a wall-clock date-time between IANA time zones with correct DST handling. Prefer this over doing timezone math yourself (a documented LLM failure mode): it uses the runtime's IANA database so offsets and daylight-saving transitions are exact. Deterministic: same input, same output. Returns the corresponding UTC instant, both zones' UTC offsets in minutes at that instant, and the converted local time. Example: {datetime:'2026-07-08T14:30', fromTz:'America/New_York', toTz:'Asia/Tokyo'} -> converted '9 Jul 2026, 03:30:00' (UTC 2026-07-08T18:30:00.000Z).