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_mission.go

@@ -0,0 +1,160 @@
+package gameserver
+
+import (
+	"encoding/json"
+	"os"
+	"sort"
+	"sync"
+
+	"gac-hkrpg-go/internal/common"
+	goproto "gac-hkrpg-go/protocol/proto"
+)
+
+// MissionUnlocks mirrors mission_unlocks.json (loaded once).
+type MissionUnlocks struct {
+	FuncUnlockMissions []uint32 `json:"funcUnlockMissions"`
+	AllMainMissions    []uint32 `json:"allMainMissions"`
+	TeleportIDs        []uint32 `json:"teleportIds"`
+	EntranceIDs        []uint32 `json:"entranceIds"`
+	RaidIDs            []uint32 `json:"raidIds"`
+	ChallengeRaidIDs   []uint32 `json:"challengeRaidIds"`
+	NpcIDs             []uint32 `json:"npcIds"`
+	SubMissionIDs      []uint32 `json:"subMissionIds"`
+	QuestIDs           []uint32 `json:"questIds"`
+}
+
+var (
+	missionUnlocksOnce sync.Once
+	missionUnlocks     MissionUnlocks
+)
+
+func getMissionUnlocks() *MissionUnlocks {
+	missionUnlocksOnce.Do(func() {
+		raw, err := os.ReadFile("mission_unlocks.json")
+		if err != nil {
+			Log("mission_unlocks.json not found: " + err.Error())
+			return
+		}
+		if err := json.Unmarshal(raw, &missionUnlocks); err != nil {
+			Log("Failed to parse mission_unlocks.json: " + err.Error())
+			missionUnlocks = MissionUnlocks{}
+			return
+		}
+		Log("Loaded mission_unlocks.json successfully")
+	})
+	return &missionUnlocks
+}
+
+func init() {
+	handle("GetMissionStatus", func(s *Session, req *goproto.GetMissionStatusCsReq, rsp *goproto.GetMissionStatusScRsp) error {
+		rsp.Retcode = 0
+		unlocks := getMissionUnlocks()
+
+		// main missions already finished: res.json + funcUnlockMissions + client-requested.
+		// Without these the client Lua locks the HUD, teleports and Endgame.
+		seen := map[uint32]bool{}
+		var finished []uint32
+		add := func(ids []uint32) {
+			for _, id := range ids {
+				if id != 0 && !seen[id] {
+					seen[id] = true
+					finished = append(finished, id)
+				}
+			}
+		}
+
+		if res, err := common.GameRes(); err == nil {
+			for _, m := range res.LevelOutputConfigs {
+				for _, sc := range m {
+					for _, grp := range sc.Scenes {
+						add(grp.FinishedMainMissions)
+					}
+				}
+			}
+		}
+		add(unlocks.FuncUnlockMissions)
+		add(req.MainMissionIdList)
+		sort.Slice(finished, func(i, j int) bool { return finished[i] < finished[j] })
+
+		rsp.FinishedMainMissionIdList = finished
+		// beta client re-asks when this field is missing (tag 13)
+		rsp.CurversionFinishedMainMissionIdList = finished
+
+		for _, id := range req.SubMissionIdList {
+			rsp.SubMissionStatusList = append(rsp.SubMissionStatusList, &goproto.Mission{
+				Id:       id,
+				Progress: 1,
+				Status:   goproto.MissionStatus_MISSION_FINISH,
+			})
+		}
+
+		SceneDebugLog("GET_MISSION_STATUS main_req=%d sub_req=%d finished_sent=%d",
+			len(req.MainMissionIdList), len(req.SubMissionIdList), len(rsp.FinishedMainMissionIdList))
+		return nil
+	})
+
+	handle("GetMissionData", func(s *Session, req *goproto.GetMissionDataCsReq, rsp *goproto.GetMissionDataScRsp) error {
+		rsp.Retcode = 0
+		unlocks := getMissionUnlocks()
+
+		seen := map[uint32]bool{}
+		var finished []uint32
+		for _, id := range unlocks.FuncUnlockMissions {
+			if id != 0 && !seen[id] {
+				seen[id] = true
+				finished = append(finished, id)
+			}
+		}
+		sort.Slice(finished, func(i, j int) bool { return finished[i] < finished[j] })
+
+		for _, id := range finished {
+			rsp.MainMissionList = append(rsp.MainMissionList, &goproto.MainMission{
+				Id:     id,
+				Status: goproto.MissionStatus_MISSION_FINISH,
+			})
+		}
+		rsp.FinishedMainMissionIdList = finished
+
+		SceneDebugLog("GET_MISSION_DATA finished_sent=%d", len(rsp.FinishedMainMissionIdList))
+		return nil
+	})
+
+	handle("GetQuestData", func(s *Session, req *goproto.GetQuestDataCsReq, rsp *goproto.GetQuestDataScRsp) error {
+		rsp.Retcode = 0
+		unlocks := getMissionUnlocks()
+		for _, id := range unlocks.QuestIDs {
+			rsp.QuestList = append(rsp.QuestList, &goproto.Quest{
+				Id:       id,
+				Status:   goproto.QuestStatus_QuestStatus_QuestFinish,
+				Progress: 1,
+			})
+		}
+		SceneDebugLog("GET_QUEST_DATA quests_sent=%d", len(rsp.QuestList))
+		return nil
+	})
+
+	// client Lua (_GetActiveGroupInfoByMissionCustomValue) reads this response;
+	// dropping it blocks input.
+	handle("GetMainMissionCustomValue", func(s *Session, req *goproto.GetMainMissionCustomValueCsReq, rsp *goproto.GetMainMissionCustomValueScRsp) error {
+		rsp.Retcode = 0
+		for _, id := range req.SubMissionIdList {
+			rsp.MainMissionList = append(rsp.MainMissionList, &goproto.MainMission{
+				Id:     id,
+				Status: goproto.MissionStatus_MISSION_FINISH,
+			})
+		}
+		SceneDebugLog("GET_MAIN_MISSION_CUSTOM_VALUE ids=%d", len(req.SubMissionIdList))
+		return nil
+	})
+
+	handle("UpdateTrackMainMission", func(s *Session, req *goproto.UpdateTrackMainMissionCsReq, rsp *goproto.UpdateTrackMainMissionScRsp) error {
+		rsp.Retcode = 0
+		rsp.TrackMissionId = req.TrackMissionId
+		return nil
+	})
+
+	handle("GetNpcMessageGroup", func(s *Session, req *goproto.GetNpcMessageGroupCsReq, rsp *goproto.GetNpcMessageGroupScRsp) error {
+		rsp.Retcode = 0
+		return nil
+	})
+}