refactor: ♻️ copy theme into the repo to customize it completly

Author: Bricklou

next.config.js

@@ -1,6 +1,10 @@
-const withNextra = require('nextra')({
-  theme: 'nextra-theme-docs',
+/** @type{import('nextra').NextraConfig} */
+const config = {
+  theme: './src/theme/index.tsx',
   themeConfig: './theme.config.tsx',
-})
+  staticImage: true
+}
+
+const withNextra = require('nextra')(config)
 
 module.exports = withNextra()