Learn: a /learn/ deep-dive section — markdown lessons as before/after spec progressions

vite.config.ts

@@ -23,9 +23,12 @@ export default defineConfig({
       // Multi-page: the marketing landing is served at `/` (index.html → the
       // lightweight `src/landing` entry); the app at `/app/` (app/index.html →
       // src/main.tsx). The app is hash-routed, so it runs unchanged under /app/.
+      // `/learn/` is the deep-dive learning section — another light marketing
+      // entry (src/learn), reusing core + the landing's chart embed only.
       input: {
         main: fileURLToPath(new URL('./index.html', import.meta.url)),
         app: fileURLToPath(new URL('./app/index.html', import.meta.url)),
+        learn: fileURLToPath(new URL('./learn/index.html', import.meta.url)),
       },
       output: {
         // Split the heavy vendors so the chunk graph stays legible and the PWA