Wire up Tailwind CSS 4, Vitest, and core app libraries

Add Tailwind (via Vite plugin), Vitest+RTL test setup, and the
Zustand/TanStack Query/Lucide libraries the architecture plan calls
for. Strip the electron-vite demo boilerplate (logo, IPC ping demo,
Versions component) in favor of a minimal placeholder screen.

Verified: typecheck, lint, and test suite all pass; pnpm dev boots
and serves the correct renderer HTML.

package.json

@@ -7,7 +7,9 @@
   "license": "MIT",
   "scripts": {
     "format": "prettier --write .",
+    "format:check": "prettier --check .",
     "lint": "eslint --cache .",
+    "lint:fix": "eslint --cache --fix .",
     "typecheck:node": "tsc --noEmit -p tsconfig.node.json --composite false",
     "typecheck:web": "tsc --noEmit -p tsconfig.web.json --composite false",
     "typecheck": "npm run typecheck:node && npm run typecheck:web",
@@ -18,20 +20,35 @@
     "build:unpack": "npm run build && electron-builder --dir",
     "build:win": "npm run build && electron-builder --win",
     "build:mac": "electron-vite build && electron-builder --mac",
-    "build:linux": "electron-vite build && electron-builder --linux"
+    "build:linux": "electron-vite build && electron-builder --linux",
+    "test": "vitest",
+    "test:run": "vitest run",
+    "test:coverage": "vitest run --coverage",
+    "test:ui": "vitest --ui"
   },
   "dependencies": {
     "@electron-toolkit/preload": "^3.0.2",
-    "@electron-toolkit/utils": "^4.0.0"
+    "@electron-toolkit/utils": "^4.0.0",
+    "@tanstack/react-query": "^5.101.4",
+    "clsx": "^2.1.1",
+    "lucide-react": "^1.28.0",
+    "tailwind-merge": "^3.6.0",
+    "zustand": "^5.0.14"
   },
   "devDependencies": {
     "@electron-toolkit/eslint-config-prettier": "^3.0.0",
     "@electron-toolkit/eslint-config-ts": "^3.1.0",
     "@electron-toolkit/tsconfig": "^2.0.0",
+    "@tailwindcss/vite": "^4.3.3",
+    "@testing-library/jest-dom": "^7.0.0",
+    "@testing-library/react": "^16.3.2",
+    "@testing-library/user-event": "^14.6.1",
     "@types/node": "^22.19.1",
     "@types/react": "^19.2.7",
     "@types/react-dom": "^19.2.3",
     "@vitejs/plugin-react": "^5.1.1",
+    "@vitest/coverage-v8": "^4.1.10",
+    "@vitest/ui": "^4.1.10",
     "electron": "^39.2.6",
     "electron-builder": "^26.0.12",
     "electron-vite": "^5.0.0",
@@ -39,10 +56,13 @@
     "eslint-plugin-react": "^7.37.5",
     "eslint-plugin-react-hooks": "^7.0.1",
     "eslint-plugin-react-refresh": "^0.4.24",
+    "jsdom": "^30.0.1",
     "prettier": "^3.7.4",
     "react": "^19.2.1",
     "react-dom": "^19.2.1",
+    "tailwindcss": "^4.3.3",
     "typescript": "^5.9.3",
-    "vite": "^7.2.6"
+    "vite": "^7.2.6",
+    "vitest": "^4.1.10"
   }
 }