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/gray-matter/CHANGELOG.md

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+# Release history
+
+## 4.0.0 - 2018-04-01
+
+### Breaking changes
+
+- Now requires node v4 or higher. 
+
+
+## 3.0.0 - 2017-06-30
+
+### Breaking changes
+
+- `toml`, `coffee` and `cson` are no longer supported by default. Please see [`options.engines`](README.md#optionsengines) and the [examples](./examples) to learn how to add engines.
+
+### Added
+
+- Support for [excerpts](README.md#optionsexcerpt).
+- The returned object now has non-enumerable `matter` and `stringify` properties.
+
+### Changed
+
+- Refactored engines (parsers), so that it's easier to add parsers and stringifiers.
+- `options.parsers` was renamed to [`options.engines`](README.md#optionsengines)