Build Verse: a poem-quote app on the agent-native chat template

Adds a Postgres-backed quotes domain (poems/quotes/favorites) exposed as
five agent-native actions (list-quotes, get-random-quote, create-quote,
toggle-favorite, list-favorites) callable from both chat and the React UI
via useActionQuery/useActionMutation. Moves the primary UI from chat to a
mobile-first Quotes/Favorites experience (chat moves to /chat), adds
manual OpenTelemetry instrumentation exporting traces/metrics/logs over
OTLP, and wires a local Docker Postgres for shared state.

app/lib/visitor-id.ts

@@ -0,0 +1,38 @@
+import { useState } from "react";
+
+const STORAGE_KEY = "verse-quote-app.visitor-id";
+
+function generateId(): string {
+  if (typeof crypto !== "undefined" && "randomUUID" in crypto) {
+    return crypto.randomUUID();
+  }
+  return `v-${Date.now()}-${Math.random().toString(36).slice(2, 10)}`;
+}
+
+/**
+ * A stable anonymous id for this browser, used to scope favorites without
+ * requiring a login. Not a real user identity — just enough to remember
+ * "your" favorites on this device.
+ */
+export function getVisitorId(): string {
+  if (typeof window === "undefined") return "";
+  try {
+    const existing = window.localStorage.getItem(STORAGE_KEY);
+    if (existing) return existing;
+    const created = generateId();
+    window.localStorage.setItem(STORAGE_KEY, created);
+    return created;
+  } catch {
+    return generateId();
+  }
+}
+
+/**
+ * React hook wrapper around getVisitorId(). Routes that use this render only
+ * an SSR loading shell (see DEVELOPING.md), so reading localStorage during
+ * the initial client render here does not cause a hydration mismatch.
+ */
+export function useVisitorId(): string {
+  const [visitorId] = useState(() => getVisitorId());
+  return visitorId;
+}