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/shared/lib/deep-readonly.d.ts

@@ -0,0 +1,8 @@
+/**
+ * A type that represents a deeply readonly object. This is similar to
+ * TypeScript's `Readonly` type, but it recursively applies the `readonly`
+ * modifier to all properties of an object and all elements of arrays.
+ */
+export type DeepReadonly<T> = T extends (infer R)[] ? ReadonlyArray<DeepReadonly<R>> : T extends object ? {
+    readonly [K in keyof T]: DeepReadonly<T[K]>;
+} : T;