Scaffold Astro/Strapi monorepo for the site rebuild

Set up a pnpm workspace with apps/site (Astro) and apps/cms (Strapi,
SQLite-backed) as the foundation for the new digital-legacy site.
Switches package management to pnpm and adds Biome for linting/
formatting, replacing npm/no-linter setup. Existing Zola site stays
in place for now and will be migrated/removed progressively.

apps/cms/src/admin/vite.config.example.ts

@@ -0,0 +1,12 @@
+import { mergeConfig, type UserConfig } from 'vite';
+
+export default (config: UserConfig) => {
+  // Important: always return the modified config
+  return mergeConfig(config, {
+    resolve: {
+      alias: {
+        '@': '/src',
+      },
+    },
+  });
+};