fix(bulk-upload): skip navigation when any chunk fails to upload

goto('/documents') fired unconditionally, discarding error chips and
leaving the user with no feedback on which files failed. Now only
navigates when hadErrors is false after all chunks complete.

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

frontend/src/lib/components/document/BulkDocumentEditLayout.svelte

@@ -92,6 +92,7 @@ async function save() {
 	}
 	chunkProgress = { done: 0, total: chunks.length };
 
+	let hadErrors = false;
 	for (let i = 0; i < chunks.length; i++) {
 		const chunk = chunks[i];
 		const formData = new FormData();
@@ -106,6 +107,7 @@ async function save() {
 		formData.append('metadata', new Blob([JSON.stringify(metadata)], { type: 'application/json' }));
 		const res = await fetch('/api/documents/quick-upload', { method: 'POST', body: formData });
 		if (!res.ok) {
+			hadErrors = true;
 			const body = await res.json().catch(() => ({ errors: [] }));
 			const errorCount = (body.errors ?? []).length;
 			for (let j = 0; j < errorCount && j < chunk.length; j++) {
@@ -115,7 +117,7 @@ async function save() {
 		}
 		chunkProgress = { done: i + 1, total: chunks.length };
 	}
-	goto('/documents');
+	if (!hadErrors) goto('/documents');
 }
 </script>