Dev server: serve paskia-js module, rework examples page

The Vite dev server now maps /paskia-js/ to the local paskia-js build
(the examples page's module import has 404'd since it was introduced,
leaving all buttons dead). Navigation actions on the examples page are
now plain same-window links so the flows' back navigation returns to
the page; added a Profile Summary button exercising profile().

frontend/vite.config.js

@@ -64,6 +64,14 @@ export default defineConfig(({ command }) => ({
         })
       }
     },
+    {
+      name: 'serve-paskia-js',
+      configureServer(server) {
+        // Serve the locally built paskia-js module for the examples page
+        const serve = sirv(resolve(__dirname, '../paskia-js'), { dev: true })
+        server.middlewares.use('/paskia-js', serve)
+      }
+    },
     {
       name: 'serve-examples',
       configureServer(server) {