Migrate accessories to user data

- Add user_accessory as the per-user accessory inventory table.
- Migrate old accessory wear records to user-owned accessory ids, including legacy common_accessory_m lookups for old installs.
- Allocate default accessories for newly created users and update accessory reads to use user_accessory at runtime.
- Validate accessory ownership when wearing accessories and keep existing accessory-based responses working.

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

internal/handler/unit/wearaccessory.go

@@ -1,7 +1,9 @@
 package unit
 
 import (
+	"errors"
 	"honoka-chan/internal/middleware"
+	usermodel "honoka-chan/internal/model/user"
 	"honoka-chan/internal/router"
 	unitschema "honoka-chan/internal/schema/unit"
 	"honoka-chan/internal/session"
@@ -32,8 +34,20 @@ func wearAccessory(ctx *gin.Context) {
 	}
 
 	// 佩戴饰品
+	var exists bool
 	for _, v := range req.Wear {
 		// fmt.Println("Wear:", v.AccessoryOwningUserID, v.UnitOwningUserID)
+		exists, err = ss.UserEng.Table(new(usermodel.UserAccessory)).
+			Where("user_id = ? AND accessory_owning_user_id = ?", ss.UserID, v.AccessoryOwningUserID).
+			Exist()
+		if ss.CheckErr(err) {
+			return
+		}
+		if !exists {
+			ss.CheckErr(errors.New("accessory not found for user"))
+			return
+		}
+
 		data := unitschema.WearAccessoryData{
 			AccessoryOwningUserID: v.AccessoryOwningUserID,
 			UnitOwningUserID:      v.UnitOwningUserID,