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/head-manager-context.shared-runtime.d.ts

@@ -0,0 +1,10 @@
+import React from 'react';
+export declare const HeadManagerContext: React.Context<{
+    updateHead?: (state: any) => void;
+    mountedInstances?: any;
+    updateScripts?: (state: any) => void;
+    scripts?: any;
+    getIsSsr?: () => boolean;
+    appDir?: boolean;
+    nonce?: string;
+}>;