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/schema/api/api.go

@@ -1,10 +1,12 @@
 package apischema
 
 type ApiReq struct {
-	Module    string `json:"module"`
-	UserID    int    `json:"user_id"`
-	Action    string `json:"action"`
-	Timestamp int64  `json:"timeStamp"`
+	Module      string `json:"module"`
+	UserID      int    `json:"user_id"`
+	Action      string `json:"action"`
+	ID          int    `json:"id"`
+	SecretBoxID int    `json:"secret_box_id"`
+	Timestamp   int64  `json:"timeStamp"`
 }
 
 type ApiResp struct {