test: add E2E tests for threads, auth, and error handling

Also fix CandidateListItem to not use Reorder.Item when isActive=false,
which caused a framer-motion crash on resolved thread detail pages.

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

src/client/components/CandidateListItem.tsx

@@ -59,13 +59,11 @@ export function CandidateListItem({
 	const openResolveDialog = useUIStore((s) => s.openResolveDialog);
 	const openExternalLink = useUIStore((s) => s.openExternalLink);
 
-	return (
-		<Reorder.Item
-			value={candidate}
-			dragControls={controls}
-			dragListener={false}
-			className="flex items-center gap-3 bg-white rounded-xl border border-gray-100 p-3 hover:border-gray-200 hover:shadow-sm transition-all group cursor-default"
-		>
+	const sharedClassName =
+		"flex items-center gap-3 bg-white rounded-xl border border-gray-100 p-3 hover:border-gray-200 hover:shadow-sm transition-all group cursor-default";
+
+	const innerContent = (
+		<>
 			{/* Drag handle */}
 			{isActive && (
 				<button
@@ -203,6 +201,22 @@ export function CandidateListItem({
 					</svg>
 				</button>
 			</div>
-		</Reorder.Item>
+		</>
 	);
+
+	// Reorder.Item requires a Reorder.Group parent — only use it in active threads
+	if (isActive) {
+		return (
+			<Reorder.Item
+				value={candidate}
+				dragControls={controls}
+				dragListener={false}
+				className={sharedClassName}
+			>
+				{innerContent}
+			</Reorder.Item>
+		);
+	}
+
+	return <div className={sharedClassName}>{innerContent}</div>;
 }