fix(lang.decorator): handle 'original' language query parameter

Added a check in the Lang decorator to return undefined if the query parameter 'lang' is set to 'original'. This change ensures that the original language is correctly processed without normalization.

Signed-off-by: Innei <tukon479@gmail.com>

Author: Innei

apps/core/src/common/decorators/lang.decorator.ts

@@ -16,6 +16,7 @@ export const Lang = createParamDecorator(
     const query = request.query as Record<string, unknown>
     const queryLang = query?.lang
     if (typeof queryLang === 'string') {
+      if (queryLang.toLowerCase() === 'original') return undefined
       const normalized = normalizeLanguageCode(queryLang)
       if (normalized) return normalized
     }