Added build:watch script/command to package.json

Should make it eaiser to automatically build the front-end when
doing local development in docker node containers.

package.json

@@ -6,6 +6,7 @@
 		"dev": "npm run pyodide:fetch && vite dev --host",
 		"dev:5050": "npm run pyodide:fetch && vite dev --port 5050",
 		"build": "npm run pyodide:fetch && vite build",
+		"build:watch": "npm run pyodide:fetch && vite build --watch",
 		"preview": "vite preview",
 		"check": "svelte-kit sync && svelte-check --tsconfig ./tsconfig.json",
 		"check:watch": "svelte-kit sync && svelte-check --tsconfig ./tsconfig.json --watch",