refactor(i18n): move Lang type to types/i18n directory

Update import paths for Lang type across layout files to use new location
Add umami analytics script in production mode

src/layouts/BlogPostLayout.astro

@@ -1,7 +1,7 @@
 ---
 import Layout from './Layout.astro';
 import type { MarkdownLayoutProps } from 'astro';
-import { type Lang } from '@/i18n/utils';
+import { type Lang } from '@/types/i18n';
 import { type FrontmatterProps } from '@/types';
 import { defaultLang } from '@/i18n/ui';
 import GlassHeader from '@/components/GlassHeader';