fix: bind window.fetch at boot so lnurlcash-kit transport works in browsers

src/boot/kit-fetch.ts

@@ -0,0 +1,14 @@
+import { defineBoot } from '#q-app';
+
+// lnurlcash-kit's transport resolves its fetch as `options.fetch ??
+// globalThis.fetch` and then invokes it as a method on the options object.
+// In a browser, calling window.fetch with any receiver other than window
+// throws a synchronous "Illegal invocation" TypeError - before any request
+// is even attempted (Node's fetch has no such receiver check, so the unit
+// tests never see it; every kit network call failed in real browsers).
+// Binding the global once here means the kit's captured default is already
+// bound, whichever receiver it is invoked with. Remove once lnurlcash-kit
+// fixes this upstream in its transport (resolveOptions).
+export default defineBoot(() => {
+  window.fetch = window.fetch.bind(window);
+});