refactor: migrate shared infrastructure, home and industries features

src/shared/layout/BodyOverlay.tsx

@@ -0,0 +1,14 @@
+"use client";
+
+import { useHeaderUI } from "./HeaderUIProvider";
+
+/**
+ * Production: `<div class="body-overlay"></div>` is a direct child of body
+ * (rendered by both index.php line 6 and header.php line 5 — production has two; we render one).
+ * CSS (consolidated into /public/css/site.css) styles it as fixed-position fullscreen overlay.
+ */
+export default function BodyOverlay() {
+  const { isMenuOpen, isSidebarOpen, closeAll } = useHeaderUI();
+  const active = isMenuOpen || isSidebarOpen;
+  return <div className={`body-overlay${active ? " active" : ""}`} onClick={closeAll} />;
+}