feat(ui): add review empty states

web/src/app/(app)/reviews/page.tsx

@@ -4,6 +4,8 @@ import { useCallback, useEffect, useMemo, useState } from "react";
 import { AppShell } from "@/components/AppShell";
 import {
   Badge,
+  EmptyState,
+  LoadingSpinner,
   Panel,
 } from "@/components/ui/Primitives";
 import {
@@ -33,6 +35,7 @@ export default function ReviewsPage() {
   const [selectedApprovalId, setSelectedApprovalId] = useState<string | null>(null);
   const [selectedBatchIds, setSelectedBatchIds] = useState<Set<string>>(new Set());
   const [reviewNote, setReviewNote] = useState("");
+  const [isLoading, setIsLoading] = useState(true);
   const [isSubmitting, setIsSubmitting] = useState(false);
   const [error, setError] = useState<string | null>(null);
 
@@ -50,6 +53,8 @@ export default function ReviewsPage() {
         setTimeline(nextTimeline);
       } catch (err) {
         setError(err instanceof Error ? err.message : "Unable to load review queue");
+      } finally {
+        setIsLoading(false);
       }
     })();
   }, []);
@@ -281,15 +286,27 @@ export default function ReviewsPage() {
             onClear={clearBatch}
             onBatchDecision={(decision) => void handleBatchDecision(decision)}
           />
-          {error ? <div style={{ color: "var(--nl-text-secondary)" }}>{error}</div> : null}
-
-          <ReviewQueueList
-            items={approvalQueue}
-            batchMode={batchMode}
-            selectedBatchIds={selectedBatchIds}
-            selectedApprovalId={featuredProposal?.id ?? null}
-            onSelectItem={(id) => batchMode ? toggleBatchItem(id) : setSelectedApprovalId(id)}
-          />
+          {isLoading ? (
+            <LoadingSpinner label="Loading review queue" className="py-8" />
+          ) : error && approvalQueue.length === 0 ? (
+            <EmptyState
+              title="Unable to load review queue"
+              description={error}
+              actionLabel="Retry"
+              onAction={() => window.location.reload()}
+            />
+          ) : (
+            <>
+              {error ? <EmptyState title="Review update failed" description={error} /> : null}
+              <ReviewQueueList
+                items={approvalQueue}
+                batchMode={batchMode}
+                selectedBatchIds={selectedBatchIds}
+                selectedApprovalId={featuredProposal?.id ?? null}
+                onSelectItem={(id) => batchMode ? toggleBatchItem(id) : setSelectedApprovalId(id)}
+              />
+            </>
+          )}
         </Panel>
       </section>
 

web/src/components/reviews/ReviewWorkflow.tsx

@@ -4,6 +4,7 @@ import { ProposalReviewCard } from "@/components/ProposalReviewCard";
 import {
   Badge,
   Button,
+  EmptyState,
   ListItemButton,
   Panel,
   PanelBody,
@@ -126,6 +127,15 @@ export function ReviewQueueList({
   selectedApprovalId: string | null;
   onSelectItem: (id: string) => void;
 }) {
+  if (items.length === 0) {
+    return (
+      <EmptyState
+        title="No proposals need review"
+        description="Agent-mediated changes that need human approval will appear here."
+      />
+    );
+  }
+
   return (
     <div style={{ display: "grid", gap: "var(--nl-space-3)" }}>
       {items.map((item) => (
@@ -212,5 +222,19 @@ export function ProposalDiffCard({
 }
 
 export function ReviewTimeline({ items }: { items: AgentTimelineItem[] }) {
+  if (items.length === 0) {
+    return (
+      <Panel>
+        <PanelHeader>
+          <PanelTitle>Agent activity timeline</PanelTitle>
+        </PanelHeader>
+        <EmptyState
+          title="No review activity yet"
+          description="Approvals, rejections, and agent changes will be listed as they happen."
+        />
+      </Panel>
+    );
+  }
+
   return <AgentTimeline items={items} />;
 }

web/src/components/ui/Primitives.tsx

@@ -23,10 +23,12 @@ import {
   DropdownMenuSub,
   DropdownMenuSubTrigger,
   DropdownMenuTrigger,
+  EmptyState as BytelystEmptyState,
   IconButton as BytelystIconButton,
   Input as BytelystInput,
   Label as BytelystLabel,
   ListItemButton as BytelystListItemButton,
+  LoadingSpinner as BytelystLoadingSpinner,
   Panel as BytelystPanel,
   PanelBody as BytelystPanelBody,
   PanelDescription as BytelystPanelDescription,
@@ -57,10 +59,12 @@ import {
   type DataListItemProps,
   type DataListProps,
   type DiffCardProps,
+  type EmptyStateProps,
   type IconButtonProps,
   type InputProps,
   type LabelProps,
   type ListItemButtonProps,
+  type LoadingSpinnerProps,
   type PanelBodyProps,
   type PanelDescriptionProps,
   type PanelHeaderProps,
@@ -297,3 +301,11 @@ export function DataListItem({ className, ...props }: DataListItemProps) {
 
 export const OperationalList = DataList;
 export const OperationalListItem = DataListItem;
+
+export function EmptyState({ className, ...props }: EmptyStateProps) {
+  return <BytelystEmptyState className={mergeClassNames("rounded-[var(--nl-radius-md)]", className)} {...props} />;
+}
+
+export function LoadingSpinner({ className, ...props }: LoadingSpinnerProps) {
+  return <BytelystLoadingSpinner className={className} {...props} />;
+}