feat(web): useSearch infinite query + useDebouncedValue + MSW search handler

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

web/src/lib/use-debounced-value.ts

@@ -0,0 +1,14 @@
+import { useEffect, useState } from "react";
+
+/** Returns `value` delayed by `delayMs`; resets the timer on each change. */
+export function useDebouncedValue<T>(value: T, delayMs: number): T {
+  const [debounced, setDebounced] = useState(value);
+
+  useEffect(() => {
+    const id = setTimeout(() => setDebounced(value), delayMs);
+
+    return () => clearTimeout(id);
+  }, [value, delayMs]);
+
+  return debounced;
+}