Implement secretbox handlers and align gacha behavior

- Add secretbox API schemas, handlers, and routes for all/showDetail/pon/multi
- Load secretbox server data through the shared serverdata loader
- Fix rarity mapping and pool rules for SR/SSR/UR special boxes
- Implement thanks festival pool behavior, including UR guarantee and SSR/UR-only rates
- Correct animation-related fields such as is_hit and lowest_rarity, and add rare UR promotion animation

Signed-off-by: Sean Du <do4suki@gmail.com>

internal/handler/api/secretbox/all.go

@@ -0,0 +1,44 @@
+package secretbox
+
+import (
+	secretboxapischema "honoka-chan/internal/schema/api/secretbox"
+	honokautils "honoka-chan/internal/utils"
+	"time"
+)
+
+func all() (res any, err error) {
+	secretBoxData, err := honokautils.LoadServerData[secretboxapischema.AllData]("secretbox_data.json")
+	if err != nil {
+		return nil, err
+	}
+
+	secretBoxData.UseCache = 0
+	secretBoxData.IsUnitMax = false
+	secretBoxData.GaugeInfo.MaxGaugePoint = 100
+	secretBoxData.GaugeInfo.GaugePoint = 0
+
+	for i := range secretBoxData.ItemList {
+		if secretBoxData.ItemList[i].Amount < 999 {
+			secretBoxData.ItemList[i].Amount = 999
+		}
+	}
+
+	for i := range secretBoxData.MemberCategoryList {
+		for j := range secretBoxData.MemberCategoryList[i].PageList {
+			for k := range secretBoxData.MemberCategoryList[i].PageList[j].ButtonList {
+				for m := range secretBoxData.MemberCategoryList[i].PageList[j].ButtonList[k].CostList {
+					secretBoxData.MemberCategoryList[i].PageList[j].ButtonList[k].CostList[m].Payable = true
+				}
+			}
+		}
+	}
+
+	res = secretboxapischema.AllResp{
+		Result:     secretBoxData,
+		Status:     200,
+		CommandNum: false,
+		TimeStamp:  time.Now().Unix(),
+	}
+
+	return res, nil
+}

internal/handler/api/secretbox/secretbox.go

@@ -0,0 +1,15 @@
+package secretbox
+
+import (
+	"fmt"
+)
+
+func SecretBoxApi(action string) (res any, err error) {
+	switch action {
+	case "all":
+		res, err = all()
+	default:
+		err = fmt.Errorf("unimplemented action: secretbox: %s", action)
+	}
+	return res, err
+}