feat(FN-968): initialize @fusion/tui workspace package

- Add @fusion/tui as a new private workspace package with ink and React dependencies
- Configure TypeScript with JSX (react-jsx), strict mode, and Node16 module resolution
- Add minimal src/index.tsx entry point with package exports
- Update root README.md with tui package reference
- Add pnpm-lock.yaml entries for ink, ink-text-input, and @types/react

packages/tui/src/index.tsx

@@ -0,0 +1,3 @@
+/** @fusion/tui — Terminal UI components for kb */
+
+export {};