fix(wails): add build:dev script for wails3 dev

Wails dev mode runs npm run build:dev before starting the app. Add the
script expected by the Taskfile so wails3 dev succeeds.

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/package.json

@@ -5,7 +5,8 @@
   "type": "module",
   "scripts": {
     "dev": "vite",
-    "build": "vite build && cp -r ../assets dist/assets",
+    "build:dev": "vite build --minify false --mode development && cp -r ../assets dist/assets",
+    "build": "vite build --mode production && cp -r ../assets dist/assets",
     "preview": "vite preview",
     "check": "svelte-check --tsconfig ./tsconfig.app.json && tsc -p tsconfig.node.json"
   },