small refactor and fixes

internal/common/crypto.go

@@ -1,7 +1,6 @@
 package common
 
 import (
-	"crypto/rand"
 	"crypto/sha512"
 	"encoding/base64"
 
@@ -14,14 +13,6 @@ func HashPassword(pwd string) []byte {
 	return h.Sum(nil)
 }
 
-func generateJWTKey(size int) string {
-	bytes := make([]byte, size)
-	if _, err := rand.Read(bytes); err != nil {
-		log.Panic().Err(err).Msg("failed to generate jwt key")
-	}
-	return base64.StdEncoding.EncodeToString(bytes)
-}
-
 func decodeJWTKey(key string) []byte {
 	if key == "" {
 		return nil