fix: stabilise happy path playwright journeys

components/reasoning-workspace.jsx

@@ -355,6 +355,7 @@ function InvestigationHistoryCard({ turn }) {
       className="rounded-lg border border-gray-100 bg-gray-50/60"
       key={turn.id}
       open={!isCollapsed}
+      data-testid="investigation-turn"
     >
       <summary className="cursor-pointer px-4 py-2 text-sm font-medium text-gray-700 hover:text-gray-900">
         {isAnswered && <span aria-hidden="true">✓ </span>}
@@ -390,13 +391,13 @@ function InvestigationHistory({ turns }) {
   const latestId = turns[turns.length - 1].id;
 
   return (
-    <div className="space-y-3">
+    <div className="space-y-3" data-testid="investigation-history">
       <h2 className="text-xs font-bold uppercase tracking-wider text-gray-400">
         Investigation history
       </h2>
       <div className="space-y-2">
         {turns.map((turn) => (
-          <InvestigationHistoryCard key={turn.id} turn={{ ...turn, _collapsed: turn.id !== latestId }} />
+          <InvestigationHistoryCard key={turn.id} data-testid="investigation-turn" turn={{ ...turn, _collapsed: turn.id !== latestId }} />
         ))}
       </div>
     </div>
@@ -490,7 +491,7 @@ function LoadingOverlay({ isLoading, elapsed, currentMessage, variant }) {
   }
 
   return (
-    <div className="rounded-lg border border-gray-200 bg-blue-50 px-5 py-6" role="status" aria-busy="true">
+    <div className="rounded-lg border border-gray-200 bg-blue-50 px-5 py-6" role="status" aria-busy="true" data-testid="loading-overlay">
       <div className="flex items-center gap-3">
         <ActivitySpinner />
         <span className="text-base font-medium text-blue-900">Working through your situation</span>
@@ -626,7 +627,7 @@ export default function ReasoningWorkspace({
     Boolean(propUnderstanding || graph?.currentSummary || result?.updatedSituationGraph?.currentSummary) || !hasSelectedQuestion;
 
   return (
-    <div className="space-y-6">
+    <div className="space-y-6" data-testid="reasoning-workspace">
       {/* ── Loading overlays ─────────────────────────────── */}
       {status === "loading" && (
         <LoadingOverlay