fix: Handle traversal navigation when canIntercept is false

For back/forward traversals, canIntercept may be false when the destination
entry was created via history.replaceState, but the URL changes regardless.
Only gate on canIntercept for push/replace navigations.

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

Author: sbesh91

src/router.js

@@ -41,21 +41,25 @@ function handleNav(state, e) {
 	// TODO: Double-check this can't fail to parse.
 	// `.destination` is read-only, so I'm hoping it guarantees a valid URL.
 	const url = new URL(e.destination.url);
+	const isTraversal = e.navigationType === 'traverse';
 
 	if (
-		!e.canIntercept ||
 		e.hashChange ||
 		e.downloadRequest !== null ||
 		!isSameWindow(e) ||
-		!isInScope(url)
+		!isInScope(url) ||
+		// For traversals (back/forward), canIntercept may be false (e.g. when the
+		// destination entry was created via history.replaceState), but the URL
+		// changes regardless — so we only gate on canIntercept for push/replace.
+		(!isTraversal && !e.canIntercept)
 	) {
 		// This is set purely for our test suite so that we can check
 		// if the event was ignored in another `navigate` handler.
 		e['preact-iso-ignored'] = true;
 		return state;
 	}
 
-	e.intercept();
+	if (e.canIntercept) e.intercept();
 	return url.href.replace(url.origin, '');
 }
 

test/router.test.js

@@ -968,12 +968,12 @@ describe('Router', () => {
 
 		expect(loc).to.deep.include({ url: '/foo', path: '/foo', searchParams: {} });
 
-		navigation.back();
+		await navigation.back().finished;
 		await sleep(10);
 
 		expect(loc).to.deep.include({ url: '/', path: '/', searchParams: {} });
 
-		navigation.forward();
+		await navigation.forward().finished;
 		await sleep(10);
 
 		expect(loc).to.deep.include({ url: '/foo', path: '/foo', searchParams: {} });