Add SolidJS + Vite PWA client scaffold

Base Vite/SolidJS project setup for the client app: build config,
static assets, and global styles.

client/vite.config.ts

@@ -0,0 +1,11 @@
+import { defineConfig } from 'vite'
+import solid from 'vite-plugin-solid'
+
+export default defineConfig({
+  plugins: [solid()],
+  server: {
+    host: true,
+    port: 5173,
+    strictPort: true,
+  },
+})