Clarify trend empty-state copy on Infrastructure summary

Swap the Infrastructure summary's placeholder strings so users see that
Pulse is actively accumulating data rather than a static empty/waiting
state:

- 'Waiting for first sample' -> 'Gathering first sample…'
- 'No history yet' -> 'Building trend history…'

Both strings are rendered in tight slots (56px sparkline card, 11px
pill) — the new copy is the same length class but signals ongoing
progress. No behavior change; Storage and Workloads summaries keep
their own wording.

frontend-modern/src/components/Infrastructure/InfrastructureSummary.test.tsx

@@ -285,7 +285,7 @@ describe('InfrastructureSummary range behavior', () => {
 
     await waitFor(() => {
       expect(container.querySelector('svg.cursor-crosshair')).toBeNull();
-      expect(container.textContent).toContain('Waiting for first sample');
+      expect(container.textContent).toContain('Gathering first sample…');
     });
   });
 
@@ -310,7 +310,7 @@ describe('InfrastructureSummary range behavior', () => {
     });
 
     await waitFor(() => {
-      expect(container.textContent).toContain('Waiting for first sample');
+      expect(container.textContent).toContain('Gathering first sample…');
     });
   });
 
@@ -620,7 +620,7 @@ describe('InfrastructureSummary range behavior', () => {
     });
 
     await waitFor(() => {
-      expect(container.textContent).not.toContain('No history yet');
+      expect(container.textContent).not.toContain('Building trend history…');
     });
   });
 

frontend-modern/src/components/Infrastructure/__tests__/UnifiedResourceTable.performance.contract.test.tsx

@@ -289,7 +289,7 @@ describe('UnifiedResourceTable performance contract', () => {
         "displaySeries().map((series) => ({",
       );
       expect(infrastructureSummaryStateSource).not.toContain(
-        "isAwaitingFirstSample() ? 'Waiting for first sample' : 'No history yet'",
+        "isAwaitingFirstSample() ? 'Gathering first sample…' : 'Building trend history…'",
       );
       expect(infrastructureSummaryStateSource).not.toContain("fetchFailed() ? 'Trend data unavailable' : emptyHistoryLabel()");
       expect(infrastructureSummaryModelSource).toContain(

frontend-modern/src/components/Infrastructure/__tests__/infrastructureSummaryModel.test.ts

@@ -157,10 +157,10 @@ describe('infrastructureSummaryModel', () => {
     ]);
     expect(hasInfrastructureSeriesData(series, 'network')).toBe(true);
     expect(hasInfrastructureSeriesData(series, 'diskio')).toBe(false);
-    expect(buildInfrastructureEmptyHistoryLabel(true)).toBe('Waiting for first sample');
-    expect(buildInfrastructureEmptyHistoryLabel(false)).toBe('No history yet');
-    expect(buildInfrastructureEmptyMessage(true, 'No history yet')).toBe('Trend data unavailable');
-    expect(buildInfrastructureEmptyMessage(false, 'No history yet')).toBe('No history yet');
+    expect(buildInfrastructureEmptyHistoryLabel(true)).toBe('Gathering first sample…');
+    expect(buildInfrastructureEmptyHistoryLabel(false)).toBe('Building trend history…');
+    expect(buildInfrastructureEmptyMessage(true, 'Building trend history…')).toBe('Trend data unavailable');
+    expect(buildInfrastructureEmptyMessage(false, 'Building trend history…')).toBe('Building trend history…');
   });
 
   it('keeps network and diskio series on canonical ids when focused summary selection narrows the view', () => {

frontend-modern/src/components/Infrastructure/infrastructureSummaryModel.ts

@@ -281,7 +281,7 @@ export function isInfrastructureAwaitingFirstSample(options: {
 }
 
 export function buildInfrastructureEmptyHistoryLabel(isAwaitingFirstSample: boolean): string {
-  return isAwaitingFirstSample ? 'Waiting for first sample' : 'No history yet';
+  return isAwaitingFirstSample ? 'Gathering first sample…' : 'Building trend history…';
 }
 
 export function buildInfrastructureEmptyMessage(

frontend-modern/src/features/dashboardOverview/__tests__/TrendCharts.test.tsx

@@ -65,7 +65,7 @@ describe('TrendCharts', () => {
           infrastructure: {
             cpu: new Map(),
             memory: new Map(),
-            emptyMessage: 'Waiting for first sample',
+            emptyMessage: 'Gathering first sample…',
           },
         })}
         overview={makeOverview()}
@@ -74,6 +74,6 @@ describe('TrendCharts', () => {
       />
     ));
 
-    expect(screen.getByText('Waiting for first sample')).toBeTruthy();
+    expect(screen.getByText('Gathering first sample…')).toBeTruthy();
   });
 });

frontend-modern/src/utils/__tests__/frontendResourceTypeBoundaries.test.ts

@@ -978,7 +978,7 @@ describe('frontend resource type boundaries', () => {
     );
     expect(infrastructureSummaryStateSource).not.toContain("displaySeries().map((series) => ({");
     expect(infrastructureSummaryStateSource).not.toContain(
-      "isAwaitingFirstSample() ? 'Waiting for first sample' : 'No history yet'",
+      "isAwaitingFirstSample() ? 'Gathering first sample…' : 'Building trend history…'",
     );
     expect(infrastructureSummaryStateSource).not.toContain("getOrgID() || 'default'");
     expect(storageSummaryCacheSource).toContain('normalizeOrgScope(getOrgID())');