fix(export): label synthetic ordinal '# Days Reach (ordinal)' to avoid collision with same-named daily field

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/src/components/ExportDataModal.jsx

@@ -51,7 +51,7 @@ export default function ExportDataModal({
   const activeDaily = useMemo(() => (dailyTemplate ?? []).filter((f) => f.active), [dailyTemplate]);
   const xOptions = useMemo(() => [
     { id: '__date__', label: 'Date' },
-    { id: '__days__', label: '# Days Reach' },
+    { id: '__days__', label: '# Days Reach (ordinal)' },
     ...activeDaily.map((f) => ({ id: f.fieldId, label: f.label })),
   ], [activeDaily]);
 

frontend/src/lib/dataExport.js

@@ -123,7 +123,7 @@ export function buildSampleIndex(statuses, xField, dailyTemplate) {
 
 function xFieldLabel(xField, dailyTemplate) {
   if (xField === '__date__') return 'Date';
-  if (xField === '__days__') return '# Days Reach';
+  if (xField === '__days__') return '# Days Reach (ordinal)';
   return (dailyTemplate ?? []).find((f) => f.fieldId === xField)?.label ?? '';
 }
 

frontend/tests/ExportDataModal.test.jsx

@@ -96,7 +96,7 @@ describe('ExportDataModal', () => {
     await waitFor(() => expect(screen.getByText(/2 rows/i)).toBeInTheDocument());
     fireEvent.click(screen.getByText('Export CSV'));
     const text = await readBlobText(dl.getBlob());
-    expect(text).toBe('Data,Total attempts\n\n# Days Reach,Alpha,Beta\n1,5,9\n2,7,');
+    expect(text).toBe('Data,Total attempts\n\n# Days Reach (ordinal),Alpha,Beta\n1,5,9\n2,7,');
     await dl.restore();
   });
 

frontend/tests/dataExport.test.js

@@ -281,7 +281,7 @@ describe('buildSubjectSeriesMatrix', () => {
       { xField: '__days__', dataParam: totalParam, groupField: '__none__' },
       { statuses: ssStatuses, animals: ssAnimals, dailyTemplate: [] },
     );
-    expect(m.corner).toBe('# Days Reach');
+    expect(m.corner).toBe('# Days Reach (ordinal)');
     expect(m.rows.map((r) => r.member.label)).toEqual(['1', '2']);
     expect(m.rows[0].values).toEqual([5, 9]);
     expect(m.rows[1].values).toEqual([7, '']);