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/revalidation-utils.d.ts

@@ -0,0 +1,6 @@
+import type { WorkStore } from './app-render/work-async-storage.external';
+/** Run a callback, and execute any *new* revalidations added during its runtime. */
+export declare function withExecuteRevalidates<T>(store: WorkStore | undefined, callback: () => Promise<T>): Promise<T>;
+type RevalidationState = Required<Pick<WorkStore, 'pendingRevalidatedTags' | 'pendingRevalidates' | 'pendingRevalidateWrites'>>;
+export declare function executeRevalidates(workStore: WorkStore, state?: RevalidationState): Promise<[void, ...any[]]>;
+export {};