Add SolidJS + Vite PWA client scaffold

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

client/tsconfig.json

@@ -0,0 +1,7 @@
+{
+  "files": [],
+  "references": [
+    { "path": "./tsconfig.app.json" },
+    { "path": "./tsconfig.node.json" }
+  ]
+}