chore: update go-mmkv dependency to v0.1.6 and refactor QMC key merging logic

internal/mmkv/mmkv.go

@@ -10,16 +10,6 @@ import (
 	"go.uber.org/zap"
 )
 
-func Merge(keys ...common.QMCKeys) common.QMCKeys {
-	result := make(common.QMCKeys)
-	for _, k := range keys {
-		for key, value := range k {
-			result[utils.NormalizeUnicode(key)] = utils.NormalizeUnicode(value)
-		}
-	}
-	return result
-}
-
 func LoadFromPath(path string, key string, logger *zap.Logger) (result common.QMCKeys, err error) {
 	mmkv_path := path
 	mmkv_crc := path + ".crc"