feat(campaign): implement Event Tent campaign system

Adds the full campaign/event-tent feature:

Packet layer:
- MsgMhfApplyCampaign: Unk0/Unk1/Unk2 → CampaignID/Code (null-terminated 16-byte string)
- MsgMhfAcquireItem: Unk0/Length/Unk1 → RewardIDs []uint32
- MsgMhfEnumerateItem: remove Unk0/Unk1 (RE'd: zeroed + always-2, ignored)
- MsgMhfStateCampaign: Unk1 → NullPadding (RE'd: always zero)
- MsgMhfTransferItem: Unk0/Unk1/Unk2 → QuestID/ItemType/Quantity (RE'd)

Handler layer (handlers_campaign.go):
- handleMsgMhfEnumerateCampaign: reads campaigns, categories, links from DB;
  prefix moved into pascal string slot 3 of each event entry (RE confirmed
  3-section response format — removes spurious intermediate section)
- handleMsgMhfStateCampaign: returns stamp count and redeemable flag
- handleMsgMhfApplyCampaign: validates and records code redemption
- handleMsgMhfEnumerateItem: lists rewards gated by stamp count
- handleMsgMhfAcquireItem: marks rewards as claimed
- handleMsgMhfTransferItem: records campaign quest completion (item_type=9)

Quest gating (handlers_quest.go):
- makeEventQuest: for QuestTypeSpecialTool, check campaign stamp count and
  deadline before allowing the quest (WriteBool true/false)

Database:
- 0010_campaign.sql: 8-table schema (campaigns, categories, links, rewards,
  claimed, state, codes, quest)
- CampaignDemo.sql: community-researched live game campaign data

network/mhfpacket/msg_mhf_transfer_item.go

@@ -11,12 +11,9 @@ import (
 // MsgMhfTransferItem represents the MSG_MHF_TRANSFER_ITEM
 type MsgMhfTransferItem struct {
 	AckHandle uint32
-	// looking at packets, these were static across sessions and did not actually
-	// correlate with any item IDs that would make sense to get after quests so
-	// I have no idea what this actually does
-	Unk0 uint32
-	Unk1 uint8
-	Unk2 uint16
+	QuestID   uint32
+	ItemType  uint8
+	Quantity  uint16
 }
 
 // Opcode returns the ID associated with this packet type.
@@ -27,10 +24,10 @@ func (m *MsgMhfTransferItem) Opcode() network.PacketID {
 // Parse parses the packet from binary
 func (m *MsgMhfTransferItem) Parse(bf *byteframe.ByteFrame, ctx *clientctx.ClientContext) error {
 	m.AckHandle = bf.ReadUint32()
-	m.Unk0 = bf.ReadUint32()
-	m.Unk1 = bf.ReadUint8()
+	m.QuestID = bf.ReadUint32()
+	m.ItemType = bf.ReadUint8()
 	bf.ReadUint8() // Zeroed
-	m.Unk2 = bf.ReadUint16()
+	m.Quantity = bf.ReadUint16()
 	return nil
 }