refactor: reorganize repo docs and tooling layout

Consolidate the repository into clearer apps, tools, and layered docs areas so contributors can navigate and maintain it more reliably. Align validation, metadata sync, and CI around the same canonical workflow to reduce drift across local checks and GitHub Actions.

apps/web-app/src/index.css

@@ -0,0 +1,15 @@
+@import "tailwindcss";
+
+@import 'github-markdown-css/github-markdown-light.css';
+
+@media (prefers-color-scheme: dark) {
+  @import 'github-markdown-css/github-markdown-dark.css';
+}
+
+:root {
+  font-family: Inter, system-ui, Avenir, Helvetica, Arial, sans-serif;
+}
+
+body {
+  @apply bg-slate-50 text-slate-900 dark:bg-slate-950 dark:text-slate-50 overflow-x-hidden;
+}