feat: scaffold Tauri v2 + React + TypeScript + shadcn/ui project

Set up Vite + React 19 + TypeScript, Tauri v2, Tailwind v4,
shadcn/ui (dark theme), and all core frontend dependencies
(Zustand, TanStack Query/Table/Virtual, CodeMirror, lucide-react).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/lib/utils.ts

@@ -0,0 +1,6 @@
+import { clsx, type ClassValue } from "clsx"
+import { twMerge } from "tailwind-merge"
+
+export function cn(...inputs: ClassValue[]) {
+  return twMerge(clsx(inputs))
+}