feat(web): frontend foundation — Tailwind terminal theme, Query, Router, Zustand + live booth screen

Add tailwindcss (Bloomberg-terminal theme in index.css), @tanstack/react-query +
react-router, zustand, and Radix primitives. Router with role-guarded routes;
QueryClient wrapping the existing apiFetch; a small Zustand live store fed by a
/api/ws client that invalidates Query caches. Booth screen: live occupancy gauge
+ streaming entry/exit/payment feed. Vite proxies the WS upgrade.

Note: BoothScreen references the pay/exit modal + active-sessions panel added in
following commits; final HEAD builds.

apps/web/src/ui/Panel.tsx

@@ -0,0 +1,33 @@
+import type { ReactNode } from "react";
+
+// Terminal panel: a bordered, titled box — the basic building block of the dense
+// booth layout. Title bar in amber, square corners, subtle layered surfaces.
+
+export function Panel({
+  title,
+  right,
+  children,
+  className = "",
+}: {
+  title?: string;
+  /** Optional right-aligned content in the title bar (e.g. a status dot). */
+  right?: ReactNode;
+  children: ReactNode;
+  className?: string;
+}) {
+  return (
+    <section
+      className={`flex flex-col border border-term-border bg-term-panel rounded-term overflow-hidden ${className}`}
+    >
+      {title && (
+        <header className="flex items-center justify-between px-3 py-1.5 bg-term-panel-2 border-b border-term-border">
+          <h2 className="m-0 text-[11px] font-semibold uppercase tracking-wider text-term-amber">
+            {title}
+          </h2>
+          {right}
+        </header>
+      )}
+      <div className="flex-1 min-h-0 p-3">{children}</div>
+    </section>
+  );
+}