test(js): cover native nav escape hatches

Cover page-swap guards that preserve native browser navigation for modified clicks, non-primary buttons, downloads, blank targets, cross-origin links, and prevented events.

req: page_swap/007

req: failure/006

slhx-js/tests/runtime.rs

@@ -115,6 +115,20 @@ fn runtime_exposes_page_swap_hooks() {
     assert!(source.contains("location.href = href"));
 }
 
+#[test]
+fn runtime_preserves_native_navigation_escape_hatches() {
+    // req: page_swap/007 req: failure/006
+    let source = slhx_js::RUNTIME_JS;
+
+    assert!(source.contains("function sameOriginNav(event, anchor)"));
+    assert!(source.contains("!event.defaultPrevented"));
+    assert!(source.contains("event.button === 0"));
+    assert!(source.contains("!event.metaKey && !event.ctrlKey && !event.shiftKey && !event.altKey"));
+    assert!(source.contains("anchor.origin === location.origin"));
+    assert!(source.contains("!anchor.download"));
+    assert!(source.contains("anchor.target !== \"_blank\""));
+}
+
 #[test]
 fn runtime_refuses_partial_updates_on_fingerprint_mismatch() {
     // req: abi/003 req: abi/004 req: runtime/004