feat(docs): add documentation site and demo features

- Introduced a new documentation site for Cursor BYOK using Next.js and Fumadocs.
- Added a product demo page with a corresponding Vite configuration.
- Implemented a demo API to simulate LLM calls and responses.
- Enhanced the Makefile to include new build and development commands for the documentation.
- Updated package.json scripts for building and running the documentation site.
- Created various components and layouts for the documentation structure, including blog and user documentation sections.
- Added styling for the new components and layouts to ensure a cohesive design.
- Included a README and other necessary files for local development and deployment.

apps/docs/eslint.config.mjs

@@ -0,0 +1,16 @@
+import { defineConfig, globalIgnores } from 'eslint/config';
+import nextVitals from 'eslint-config-next/core-web-vitals';
+
+const eslintConfig = defineConfig([
+  ...nextVitals,
+  globalIgnores([
+    '.next/**',
+    'out/**',
+    'build/**',
+    'next-env.d.ts',
+    '.source/**',
+    'public/product-demo/**',
+  ]),
+]);
+
+export default eslintConfig;