refactor: Gitea 式目录改组，移除本分支 SPA 与杂项产物

将 model/service/handler/middleware 迁至 models/services/routers/api/modules/auth，并删除 frontend、embed_static、scripts 及误入库缓存/二进制。

Co-authored-by: Cursor <cursoragent@cursor.com>

services/settings_util.go

@@ -0,0 +1,14 @@
+package service
+
+import (
+	"strings"
+	"unicode/utf8"
+)
+
+func runeLen(s string) int {
+	return utf8.RuneCountInString(s)
+}
+
+func trimRunes(s string) string {
+	return strings.TrimSpace(s)
+}