feat(confidence-engine): use server investigation persistence

app/investigations/[id]/page.jsx

@@ -11,10 +11,21 @@ export default function InvestigationPage({ params }) {
   const router = useRouter();
   const routeId = typeof params?.id === "string" ? params.id : "";
   const [existing, setExisting] = useState(null);
+  const [hydrated, setHydrated] = useState(false);
 
   useEffect(() => {
-    if (!routeId) return;
-    setExisting(loadInvestigation(routeId));
+    let active = true;
+    setHydrated(false);
+    if (!routeId) { setHydrated(true); return; }
+    (async () => {
+      try {
+        const snapshot = await loadInvestigation(routeId);
+        if (active) setExisting(snapshot);
+      } finally {
+        if (active) setHydrated(true);
+      }
+    })();
+    return () => { active = false; };
   }, [routeId]);
 
   return (
@@ -35,7 +46,9 @@ export default function InvestigationPage({ params }) {
         evidence-based structured reconstruction. This is a technical vertical
         slice — not a production system.
       </p>
-      {existing ? (
+      {!hydrated ? (
+        <p className="text-sm text-gray-500">Loading investigation…</p>
+      ) : existing ? (
         <ScenarioForm
           investigationId={routeId}
           existingSnapshot={existing}

app/investigations/[id]/report/page.jsx

@@ -15,9 +15,20 @@ export default function ReportPage({ params }) {
   const generationAttempted = useRef(false);
 
   useEffect(() => {
-    setExisting(loadInvestigation(routeId));
-    setHydrated(true);
-  }, []);
+    let active = true;
+    setHydrated(false);
+    (async () => {
+      try {
+        const snapshot = await loadInvestigation(routeId);
+        if (active) setExisting(snapshot);
+      } catch {
+        if (active) setGenerationError(true);
+      } finally {
+        if (active) setHydrated(true);
+      }
+    })();
+    return () => { active = false; };
+  }, [routeId]);
 
   // First-generation: create report when none persists (v0.58)
   useEffect(() => {
@@ -54,7 +65,8 @@ export default function ReportPage({ params }) {
           const rev = existing?.investigationRevision ?? 0;
           const reportData = { understanding: data.understanding, plausibleInterpretations: data.plausibleInterpretations, hasPlausibleInterpretations: true, generatedFromRevision: rev };
           setExisting((p) => {
-            saveInvestigation({ ...p, investigationReport: reportData });
+            void saveInvestigation({ ...p, investigationReport: reportData })
+              .catch((error) => console.error("Investigation report save failed", error));
             return { ...p, investigationReport: reportData };
           });
         } else {
@@ -73,7 +85,7 @@ export default function ReportPage({ params }) {
     if (updateLoading) return;
     setUpdateLoading(true);
 
-    const snap = loadInvestigation(routeId);
+    const snap = await loadInvestigation(routeId);
     const situationGraph = snap?.situationGraph;
     const findings = snap?.findings ?? [];
     const rev = snap?.investigationRevision ?? 0;
@@ -99,7 +111,8 @@ export default function ReportPage({ params }) {
       if (data.success) {
         const reportData = { understanding: data.understanding, plausibleInterpretations: data.plausibleInterpretations, hasPlausibleInterpretations: true, generatedFromRevision: rev };
         setExisting((p) => {
-          saveInvestigation({ ...p, investigationReport: reportData });
+          void saveInvestigation({ ...p, investigationReport: reportData })
+            .catch((error) => console.error("Investigation report save failed", error));
           return { ...p, investigationReport: reportData };
         });
       }