fix: fail safe on missing workspace revisions

frontend/src/shell/WorkspaceManager.tsx

@@ -63,11 +63,12 @@ export function WorkspaceManager({ open, onClose }: { open: boolean; onClose: ()
   const workspacesQuery = useQuery({ queryKey: ["workspaces"], queryFn: listWorkspaces, enabled: open });
   const workspaces = workspacesQuery.data ?? [];
   const selectedSummary = useMemo(() => workspaces.find((workspace) => workspace.id === selectedId), [selectedId, workspaces]);
-  const selectedIsLegacy = selectedSummary?.revision.state === "migration_required";
+  const selectedSummaryIncomplete = Boolean(selectedSummary && !selectedSummary.revision);
+  const selectedIsLegacy = selectedSummary?.revision?.state === "migration_required";
   const detailQuery = useQuery({
     queryKey: ["workspace", selectedId],
     queryFn: () => getWorkspace(selectedId!),
-    enabled: Boolean(open && selectedId && !localDraft && !selectedIsLegacy),
+    enabled: Boolean(open && selectedId && !localDraft && !selectedSummaryIncomplete && !selectedIsLegacy),
   });
   const status = statusQuery.data;
   const record = detailQuery.data;
@@ -311,13 +312,18 @@ export function WorkspaceManager({ open, onClose }: { open: boolean; onClose: ()
           </nav>
 
           <div className="min-w-0 overflow-y-auto px-5 py-5">
-            {selectedIsLegacy ? (
+            {selectedSummaryIncomplete ? (
+              <div className="rounded-md border border-amber-500/30 bg-amber-500/10 px-4 py-3 text-sm">
+                <p className="font-semibold">Workspace summary unavailable</p>
+                <p className="mt-1">This workspace summary is incomplete. Refresh the registry or choose another workspace before creating sessions or editing drafts.</p>
+              </div>
+            ) : selectedIsLegacy ? (
               <div className="rounded-md border border-amber-500/30 bg-amber-500/10 px-4 py-3 text-sm">
                 <p className="font-semibold">Migration required</p>
                 <p className="mt-1">This workspace uses a legacy descriptor and must be migrated to schema v3 before new sessions or publication.</p>
               </div>
             ) : detailQuery.isError && selectedId && !localDraft ? <QueryError name="Workspace details failed" message="Could not load workspace details." retryLabel="Retry workspace details" onRetry={() => { void detailQuery.refetch(); }} /> : !currentDraft && !detailQuery.isLoading && <div className="grid min-h-64 place-items-center text-center"><div><h3 className="font-heading font-semibold">Select a workspace</h3><p className="mt-1 text-sm text-muted-foreground">Review an existing definition or start a browser-only draft.</p></div></div>}
-            {!selectedIsLegacy && !detailQuery.isError && (currentDraft || detailQuery.isLoading) && (
+            {!selectedSummaryIncomplete && !selectedIsLegacy && !detailQuery.isError && (currentDraft || detailQuery.isLoading) && (
               <>
                 {detailQuery.isLoading && !currentDraft ? <p className="text-sm text-muted-foreground">Loading workspace definition…</p> : currentDraft && <>
                   <div className="mb-5 flex flex-wrap items-start justify-between gap-3 border-b border-border/70 pb-4">