feat: integrate Just Works app and native business setup

Preserve hosted website UX inside Archipelago, add isolated Business and owner-authorized native wallet setup, and include deployment handoff. Based on main with native signer import already accepted.

docker/justworks/public/assets/ds/header.js

@@ -0,0 +1,24 @@
+/*
+ * Top bar scroll state — shared with the main site's behaviour.
+ * Transparent while parked; past the first 80px the bar earns the
+ * translucent ground, hairline and blur. Toggles `is-scrolled`.
+ */
+const SCROLL_START = 80;
+
+export function startNavScroll(bar = document.querySelector("[data-topbar]")) {
+  if (!bar) return () => {};
+  let frame = 0;
+  const apply = () => {
+    frame = 0;
+    bar.classList.toggle("is-scrolled", window.scrollY > SCROLL_START);
+  };
+  const onScroll = () => {
+    if (!frame) frame = requestAnimationFrame(apply);
+  };
+  apply();
+  window.addEventListener("scroll", onScroll, { passive: true });
+  return () => {
+    window.removeEventListener("scroll", onScroll);
+    if (frame) cancelAnimationFrame(frame);
+  };
+}