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/client/compat/router.d.ts

@@ -0,0 +1,12 @@
+import type { NextRouter } from '../router';
+/**
+ * useRouter from `next/compat/router` is designed to assist developers
+ * migrating from `pages/` to `app/`. Unlike `next/router`, this hook does not
+ * throw when the `NextRouter` is not mounted, and instead returns `null`. The
+ * more concrete return type here lets developers use this hook within
+ * components that could be shared between both `app/` and `pages/` and handle
+ * to the case where the router is not mounted.
+ *
+ * @returns The `NextRouter` instance if it's available, otherwise `null`.
+ */
+export declare function useRouter(): NextRouter | null;