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/server/lib/lazy-result.d.ts

@@ -0,0 +1,13 @@
+export type LazyResult<TValue> = PromiseLike<TValue> & {
+    value?: TValue;
+};
+export type ResolvedLazyResult<TValue> = PromiseLike<TValue> & {
+    value: TValue;
+};
+/**
+ * Calls the given function only when the returned promise-like object is
+ * awaited. Afterwards, it provides the resolved value synchronously as `value`
+ * property.
+ */
+export declare function createLazyResult<TValue>(fn: () => Promise<TValue> | TValue): LazyResult<TValue>;
+export declare function isResolvedLazyResult<TValue>(result: LazyResult<TValue>): result is ResolvedLazyResult<TValue>;