- RegisterUntilLow now panics if startIndex > endIndex (programmer
must address version incompatibility explicitly, not silently skip)
- Replace per-version RegisterCritical handlers with dual-range
RegisterUntil: modern range (v1_21_8->latest) + legacy range (v1_8->1.12.2)
- Remove v1_12_2 handler duplicates (covered by upward range from v1_8)
- Move legacy chat handling into chat.Module.SendMessage (protocol<764
uses v1_8.PlayToServerPacketChat instead of v1_21_11)
- Skip chat signing init for pre-1.19 versions