fix(items): stop G-rank Workshop/Cog softlock on missing ACK

MSG_MHF_GET_EXTRA_INFO (0xA6) and MSG_MHF_GET_COG_INFO (0xC3) had
Parse() returning NOT IMPLEMENTED. The dispatch loop treats any Parse
error as a hard drop — no ACK is ever sent, so the client waits
indefinitely and effectively soft-locks when entering the G-rank
Workshop or Master Felyne (Cog) screens.

Fix: parse AckHandle (the only field we can confirm from the protocol)
and respond with doAckBufFail so the client receives a well-formed
buf-type ACK with error code 1. The client's fail branch for these
requests exits cleanly without reading response fields, avoiding the
read-past-EOF crash that an empty success ACK would cause.

The full response format for both packets is still unknown; a complete
implementation requires further RE. The TODO comments mark the gap.

Fixes #180.

network/mhfpacket/msg_mhf_get_extra_info.go

@@ -9,7 +9,9 @@ import (
 )
 
 // MsgMhfGetExtraInfo represents the MSG_MHF_GET_EXTRA_INFO
-type MsgMhfGetExtraInfo struct{}
+type MsgMhfGetExtraInfo struct {
+	AckHandle uint32
+}
 
 // Opcode returns the ID associated with this packet type.
 func (m *MsgMhfGetExtraInfo) Opcode() network.PacketID {
@@ -18,7 +20,8 @@ func (m *MsgMhfGetExtraInfo) Opcode() network.PacketID {
 
 // Parse parses the packet from binary
 func (m *MsgMhfGetExtraInfo) Parse(bf *byteframe.ByteFrame, ctx *clientctx.ClientContext) error {
-	return errors.New("NOT IMPLEMENTED")
+	m.AckHandle = bf.ReadUint32()
+	return nil
 }
 
 // Build builds a binary packet from the current data.