feat(blog): add file-based blog with dynamic slugs, MDX content and layout shell

- Introduced blog routing using Next.js App Router
- Implemented dynamic [slug] pages for blog posts
- Added MDX-based content loading via lib/posts
- Integrated shared TopBar layout with navigation
- Established clear content, lib and component separation

apps/public-web/node_modules/next/dist/lib/metadata/constants.d.ts

@@ -0,0 +1,6 @@
+import type { ViewportLayout } from './types/extra-types';
+import type { Icons } from './types/metadata-types';
+export declare const ViewportMetaKeys: {
+    [k in keyof ViewportLayout]: string;
+};
+export declare const IconKeys: (keyof Icons)[];