feat(dashboard): filter provider comparison differences

apps/dashboard/src/components/AnalyticsTab.test.tsx

@@ -93,6 +93,128 @@ function compareResponse(): CompareResponse {
   };
 }
 
+function differingCompareResponse(): CompareResponse {
+  return {
+    experiments: ['model-compare'],
+    targets: ['gpt-5.4', 'gpt-5.4-mini'],
+    cells: [
+      {
+        experiment: 'model-compare',
+        target: 'gpt-5.4',
+        eval_count: 2,
+        quality_count: 2,
+        passed_count: 1,
+        pass_rate: 0.5,
+        avg_score: 0.5,
+        tests: [],
+      },
+      {
+        experiment: 'model-compare',
+        target: 'gpt-5.4-mini',
+        eval_count: 2,
+        quality_count: 2,
+        passed_count: 2,
+        pass_rate: 1,
+        avg_score: 1,
+        tests: [],
+      },
+    ],
+    runs: [
+      {
+        run_id: '2026-07-07T14-06-40-813Z',
+        started_at: '2026-07-07T14:06:40.813Z',
+        experiment: 'model-compare',
+        target: '2 providers',
+        targets: ['gpt-5.4', 'gpt-5.4-mini'],
+        source: 'local',
+        eval_count: 4,
+        quality_count: 4,
+        passed_count: 3,
+        pass_rate: 0.75,
+        avg_score: 0.75,
+        tests: [
+          {
+            test_id: 'matching-row',
+            target: 'gpt-5.4',
+            score: 1,
+            passed: true,
+            execution_status: 'ok',
+            answer: 'same answer',
+          },
+          {
+            test_id: 'matching-row',
+            target: 'gpt-5.4-mini',
+            score: 1,
+            passed: true,
+            execution_status: 'ok',
+            answer: 'same answer',
+          },
+          {
+            test_id: 'answer-differs',
+            target: 'gpt-5.4',
+            score: 1,
+            passed: true,
+            execution_status: 'ok',
+            answer: 'alpha answer',
+          },
+          {
+            test_id: 'answer-differs',
+            target: 'gpt-5.4-mini',
+            score: 1,
+            passed: true,
+            execution_status: 'ok',
+            answer: 'beta answer',
+          },
+          {
+            test_id: 'status-differs',
+            target: 'gpt-5.4',
+            score: 1,
+            passed: true,
+            execution_status: 'ok',
+            answer: 'completed',
+          },
+          {
+            test_id: 'status-differs',
+            target: 'gpt-5.4-mini',
+            score: 0,
+            passed: false,
+            execution_status: 'execution_error',
+            answer: 'completed',
+          },
+        ],
+      },
+    ],
+  };
+}
+
+function matchingCompareResponse(): CompareResponse {
+  const data = differingCompareResponse();
+  return {
+    ...data,
+    runs: data.runs?.map((run) => ({
+      ...run,
+      tests: [
+        {
+          test_id: 'matching-row',
+          target: 'gpt-5.4',
+          score: 1,
+          passed: true,
+          execution_status: 'ok',
+          answer: 'same answer',
+        },
+        {
+          test_id: 'matching-row',
+          target: 'gpt-5.4-mini',
+          score: 1,
+          passed: true,
+          execution_status: 'ok',
+          answer: 'same answer',
+        },
+      ],
+    })),
+  };
+}
+
 describe('AnalyticsTab provider/model comparison', () => {
   it('renders same-test provider/model outputs side by side', () => {
     const queryClient = new QueryClient();
@@ -112,4 +234,45 @@ describe('AnalyticsTab provider/model comparison', () => {
     expect(html).toContain('Answer');
     expect(html).toContain('result_dir=exact-token-gpt54');
   });
+
+  it('filters provider/model comparison rows to differing outputs', () => {
+    const queryClient = new QueryClient();
+    const html = renderToStaticMarkup(
+      <QueryClientProvider client={queryClient}>
+        <AnalyticsTab
+          data={differingCompareResponse()}
+          isLoading={false}
+          isError={false}
+          defaultProviderModelDisplayMode="differing"
+        />
+      </QueryClientProvider>,
+    );
+
+    expect(html).toContain('All');
+    expect(html).toContain('Differing');
+    expect(html).toContain('answer-differs');
+    expect(html).toContain('alpha answer');
+    expect(html).toContain('beta answer');
+    expect(html).toContain('status-differs');
+    expect(html).toContain('error');
+    expect(html).not.toContain('matching-row');
+  });
+
+  it('shows an empty state when all provider/model comparison rows match', () => {
+    const queryClient = new QueryClient();
+    const html = renderToStaticMarkup(
+      <QueryClientProvider client={queryClient}>
+        <AnalyticsTab
+          data={matchingCompareResponse()}
+          isLoading={false}
+          isError={false}
+          defaultProviderModelDisplayMode="differing"
+        />
+      </QueryClientProvider>,
+    );
+
+    expect(html).toContain('All compared rows match');
+    expect(html).toContain('Switch back to All rows to inspect the full provider/model table.');
+    expect(html).not.toContain('matching-row');
+  });
 });