feat(FN-969): scaffold TUI package with Ink entry point and vitest config

- Create @fusion/tui package structure with ink and react dependencies
- Add basic App component entry point using Ink's Box and Text primitives
- Configure vitest with passWithNoTests and coverage settings
- Fix tsconfig to exclude vitest/globals types from production build

packages/tui/package.json

@@ -13,20 +13,22 @@
     "README.md"
   ],
   "scripts": {
+    "dev": "tsx src/index.tsx",
     "build": "tsc",
     "typecheck": "tsc --noEmit",
-    "test": "echo 'No tests yet' && exit 0"
+    "test": "vitest run"
   },
   "dependencies": {
-    "@fusion/core": "workspace:*",
     "ink": "^6.8.0",
-    "ink-text-input": "^6.0.0",
     "react": "^19.0.0"
   },
   "devDependencies": {
     "@types/node": "^25.5.0",
     "@types/react": "^19.0.0",
-    "typescript": "^5.7.0"
+    "@vitest/coverage-v8": "^3.1.0",
+    "tsx": "^4.19.0",
+    "typescript": "^5.7.0",
+    "vitest": "^3.1.0"
   },
   "engines": {
     "node": ">=22.5.0"

packages/tui/src/index.tsx

@@ -1,3 +1,12 @@
 /** @fusion/tui — Terminal UI components for kb */
 
-export {};
+import { render, Text } from "ink";
+import React from "react";
+
+/** Main application component for dev mode */
+function App() {
+  return <Text>Hello from @fusion/tui!</Text>;
+}
+
+// When run directly via `pnpm dev`, render the app
+render(<App />);

packages/tui/vitest.config.ts

@@ -0,0 +1,19 @@
+import { defineConfig } from "vitest/config";
+
+const maxWorkers = Number.parseInt(process.env.VITEST_MAX_WORKERS ?? "16", 10);
+
+export default defineConfig({
+  test: {
+    include: ["src/**/*.test.ts", "src/**/*.test.tsx"],
+    passWithNoTests: true,
+    maxWorkers,
+    fileParallelism: true,
+    coverage: {
+      enabled: false,
+      reporter: ["text", "html", "json"],
+      reportsDirectory: "./coverage",
+      include: ["src/**/*.ts", "src/**/*.tsx"],
+      exclude: ["**/*.test.ts", "**/*.test.tsx", "**/*.d.ts", "dist/**"],
+    },
+  },
+});