Dev server updates (#52)

* Start dev server on any port

* Move dev DB into project folder

* Choose free ports for dev server

* Reliability

* Both processes get env vars

* And open browser

frontend/vite.config.ts

@@ -11,10 +11,10 @@ export default defineConfig({
     },
   },
   server: {
-    port: 3000,
+    port: parseInt(process.env.FRONTEND_PORT || '3000'),
     proxy: {
       '/api': {
-        target: 'http://localhost:3001',
+        target: `http://localhost:${process.env.BACKEND_PORT || '3001'}`,
         changeOrigin: true,
       },
     },