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/index.css

@@ -0,0 +1,58 @@
+@import "tailwindcss";
+
+/* Bloomberg-terminal aesthetic: dense, dark, monospace, keyboard-first.
+   Tailwind v4 — design tokens live here in @theme (no tailwind.config.js).
+   The booth runs on a fixed appliance display; we optimise for a dark room,
+   glanceable status colour, and high information density over whitespace. */
+@theme {
+  /* Surfaces — near-black, layered greys for panels/borders. */
+  --color-term-bg: #0a0e12;
+  --color-term-panel: #11161c;
+  --color-term-panel-2: #161d25;
+  --color-term-border: #232c37;
+  --color-term-muted: #6b7785;
+  --color-term-text: #c9d3de;
+
+  /* Status accents — the terminal's signal colours. */
+  --color-term-amber: #f5a623;   /* primary accent / headings / focus */
+  --color-term-green: #2ecc71;   /* entry / ok / free */
+  --color-term-red: #ff4d4f;     /* exit / fault / full */
+  --color-term-cyan: #38bdf8;    /* payment / info */
+
+  /* Monospace stack — IBM Plex Mono / JetBrains first, system mono fallback. */
+  --font-mono: "JetBrains Mono", "IBM Plex Mono", ui-monospace, "SFMono-Regular",
+    "Menlo", "Consolas", monospace;
+
+  /* Tight radius — terminals are square. */
+  --radius-term: 2px;
+}
+
+html,
+body,
+#root {
+  height: 100%;
+}
+
+body {
+  margin: 0;
+  background: var(--color-term-bg);
+  color: var(--color-term-text);
+  font-family: var(--font-mono);
+  font-size: 13px;
+  line-height: 1.4;
+  -webkit-font-smoothing: antialiased;
+  /* Crisp text and no rubber-banding on the fixed appliance display. */
+  overscroll-behavior: none;
+}
+
+/* Terminal scrollbars — thin, dark, unobtrusive. */
+* {
+  scrollbar-width: thin;
+  scrollbar-color: var(--color-term-border) transparent;
+}
+
+/* A visible keyboard-focus ring in the amber accent (keyboard-first UI). */
+:focus-visible {
+  outline: 1px solid var(--color-term-amber);
+  outline-offset: 1px;
+}