feat: port GaC-hkrpg-ps to Go with SceneCastSkill camera-detach fix

- mihoyo-variant KCP in pure Go (28-byte conv+token header), UDP gateway
  with 0xFF/0x145/0x194 handshake, ms-precision KCP clock + retransmit ticker
- protobuf for 4.6.51 generated from the AstralOS StarRail.proto (4932
  messages) plus CmdID map from // CmdID: comments (2114 ids)
- sdkserver port: query_dispatch/query_gateway (Gateserver pb + base64),
  hotfix fetch, auth endpoints, SRTools freesr-data.json upload
- gameserver handlers: login flow, scene load/spawn with real monster
  entity tracking, lineup, avatar/skin, missions, tutorials (1249+855),
  bag/equip, challenge incl. StartChallenge 1787 layout + Tierce 8973 +
  peak 8948, all raw tierce replies
- SceneCastSkill camera bug fix: only real scene monsters (tracked per
  session) trigger battle; attacking props/NPCs/air replies retcode 0
  without battle_info so the camera stays locked on the character
- end-to-end smoke test simulating a client over real UDP: handshake,
  PlayerGetToken, and both SceneCastSkill paths
- reuses the Rust PS data files unchanged (freesr-data.json, persistent,
  res.json, teleports.json, challenge_data.json, mission_unlocks.json)

internal/gameserver/handlers_lineup.go

@@ -0,0 +1,150 @@
+package gameserver
+
+import (
+	"gac-hkrpg-go/internal/common"
+	goproto "gac-hkrpg-go/protocol/proto"
+)
+
+func commonToLineupAvatars(f *common.FreesrData) []*goproto.LineupAvatar {
+	return common.ToLineupAvatars(f)
+}
+
+func init() {
+	handle("GetAllLineupData", func(s *Session, req *goproto.GetAllLineupDataCsReq, rsp *goproto.GetAllLineupDataScRsp) error {
+		player := s.JSON()
+		if player == nil {
+			return nil
+		}
+		rsp.LineupList = append(rsp.LineupList, &goproto.LineupInfo{
+			ExtraLineupType: goproto.ExtraLineupType_ExtraLineupType_LineupNone,
+			Name:            "Squad 1",
+			Mp:              5,
+			MaxMp:           5,
+			AvatarList:      commonToLineupAvatars(player),
+		})
+		return nil
+	})
+
+	handle("GetCurLineupData", func(s *Session, req *goproto.GetCurLineupDataCsReq, rsp *goproto.GetCurLineupDataScRsp) error {
+		player := s.JSON()
+		if player == nil {
+			return nil
+		}
+		rsp.Lineup = &goproto.LineupInfo{
+			ExtraLineupType: goproto.ExtraLineupType_ExtraLineupType_LineupNone,
+			Name:            "Squad 1",
+			Mp:              5,
+			MaxMp:           5,
+			AvatarList:      commonToLineupAvatars(player),
+		}
+		return nil
+	})
+
+	handle("JoinLineup", func(s *Session, req *goproto.JoinLineupCsReq, rsp *goproto.JoinLineupScRsp) error {
+		player := s.JSON()
+		if player == nil {
+			return nil
+		}
+		player.Lineups[req.Slot] = req.BaseAvatarId
+		player.SavePersistent()
+		return refreshLineup(s)
+	})
+
+	handle("ReplaceLineup", func(s *Session, req *goproto.ReplaceLineupCsReq, rsp *goproto.ReplaceLineupScRsp) error {
+		player := s.JSON()
+		if player == nil {
+			return nil
+		}
+		for _, item := range req.LineupSlotList {
+			player.Lineups[item.Slot] = item.Id
+		}
+		player.SavePersistent()
+		return refreshLineup(s)
+	})
+
+	handle("SwapLineup", func(s *Session, req *goproto.SwapLineupCsReq, rsp *goproto.SwapLineupScRsp) error {
+		player := s.JSON()
+		if player == nil {
+			return nil
+		}
+		// MPIEGFCNBEN / ENBIBCPPLDC are the obfuscated src/dst slots; the swap
+		// is symmetric so the mapping direction doesn't matter.
+		srcSlot, dstSlot := req.MPIEGFCNBEN, req.ENBIBCPPLDC
+		srcAvatar := player.Lineups[srcSlot]
+		dstAvatar := player.Lineups[dstSlot]
+		player.Lineups[srcSlot] = dstAvatar
+		player.Lineups[dstSlot] = srcAvatar
+		player.SavePersistent()
+		return refreshLineup(s)
+	})
+
+	handle("SwitchLineupIndex", func(s *Session, req *goproto.SwitchLineupIndexCsReq, rsp *goproto.SwitchLineupIndexScRsp) error {
+		return refreshLineup(s)
+	})
+
+	handle("GetLineupAvatarData", func(s *Session, req *goproto.GetLineupAvatarDataCsReq, rsp *goproto.GetLineupAvatarDataScRsp) error {
+		rsp.Retcode = 0
+		return nil
+	})
+
+	handle("QuitLineup", func(s *Session, req *goproto.QuitLineupCsReq, rsp *goproto.QuitLineupScRsp) error {
+		return nil
+	})
+
+	handle("ChangeLineupLeader", func(s *Session, req *goproto.ChangeLineupLeaderCsReq, rsp *goproto.ChangeLineupLeaderScRsp) error {
+		rsp.Slot = req.Slot
+		return nil
+	})
+}
+
+// refreshLineup mirrors refresh_lineup: SceneGroupRefreshScNotify + SyncLineupNotify.
+func refreshLineup(s *Session) error {
+	player := s.JSON()
+	if player == nil {
+		return nil
+	}
+
+	lineup := &goproto.LineupInfo{
+		ExtraLineupType: goproto.ExtraLineupType_ExtraLineupType_LineupNone,
+		Name:            "Squad 1",
+		AvatarList:      commonToLineupAvatars(player),
+		MaxMp:           5,
+		Mp:              5,
+	}
+
+	notify := &goproto.SceneGroupRefreshScNotify{
+		FloorId:     player.Scene.FloorID,
+		DimensionId: 0,
+	}
+	group := &goproto.SceneGroupRefreshInfo{
+		GroupId:          0,
+		State:            0,
+		GroupRefreshType: goproto.SceneGroupRefreshType_SCENE_GROUP_REFRESH_TYPE_LOADED,
+	}
+	for _, slot := range player.SortedLineupKeys() {
+		avatarID := player.Lineups[slot]
+		group.RefreshEntity = append(group.RefreshEntity, &goproto.SceneEntityRefreshInfo{
+			RefreshType: &goproto.SceneEntityRefreshInfo_AddEntity{
+				AddEntity: &goproto.SceneEntityInfo{
+					EntityId: slot + 1,
+					GroupId:  0,
+					InstId:   0,
+					Entity: &goproto.SceneEntityInfo_Actor{
+						Actor: &goproto.SceneActorInfo{
+							AvatarType:   goproto.AvatarType_AVATAR_FORMAL_TYPE,
+							BaseAvatarId: avatarID,
+							MapLayer:     0,
+							Uid:          25,
+						},
+					},
+				},
+			},
+		})
+	}
+	notify.GroupRefreshInfo = append(notify.GroupRefreshInfo, group)
+
+	if err := s.Send(notify); err != nil {
+		return err
+	}
+	return s.Send(&goproto.SyncLineupNotify{Lineup: lineup})
+}