spec(prometheus-direct-charting): verify + close SC-125 + reconcile tracking

Add loading-state tests to the three Prometheus widget test files
(closes SC-125 PARTIAL). Write apply-progress.md, tick all 39 tasks,
add verify-report.md (26/27 PASS, 1 PARTIAL->PASS). All gates green:
293 pytest, ruff clean, npm build+lint 0 errors. No blocking findings.

frontend/src/widgets/__tests__/PrometheusChartWidget.test.tsx

@@ -30,6 +30,17 @@ function mockData(data: unknown, error?: string) {
 }
 
 describe("PrometheusChartWidget", () => {
+	it("renders skeleton while loading", () => {
+		vi.mocked(useWidgets.useWidgetData).mockReturnValue({
+			data: undefined,
+			isLoading: true,
+		} as unknown as ReturnType<typeof useWidgets.useWidgetData>);
+		render(<PrometheusChartWidget widget={widget} refreshIntervalMs={60000} />);
+		expect(
+			document.querySelector('[data-slot="skeleton"]'),
+		).toBeInTheDocument();
+	});
+
 	it("renders a chart with series data", () => {
 		mockData({
 			series: [

frontend/src/widgets/__tests__/PrometheusGaugeWidget.test.tsx

@@ -30,6 +30,17 @@ function mockData(data: unknown, error?: string) {
 }
 
 describe("PrometheusGaugeWidget", () => {
+	it("renders skeleton while loading", () => {
+		vi.mocked(useWidgets.useWidgetData).mockReturnValue({
+			data: undefined,
+			isLoading: true,
+		} as unknown as ReturnType<typeof useWidgets.useWidgetData>);
+		render(<PrometheusGaugeWidget widget={widget} refreshIntervalMs={30000} />);
+		expect(
+			document.querySelector('[data-slot="skeleton"]'),
+		).toBeInTheDocument();
+	});
+
 	it("renders a gauge with value and threshold bands", () => {
 		mockData({
 			value: 0.75,

frontend/src/widgets/__tests__/PrometheusMeanWidget.test.tsx

@@ -30,6 +30,17 @@ function mockData(data: unknown, error?: string) {
 }
 
 describe("PrometheusMeanWidget", () => {
+	it("renders skeleton while loading", () => {
+		vi.mocked(useWidgets.useWidgetData).mockReturnValue({
+			data: undefined,
+			isLoading: true,
+		} as unknown as ReturnType<typeof useWidgets.useWidgetData>);
+		render(<PrometheusMeanWidget widget={widget} refreshIntervalMs={60000} />);
+		expect(
+			document.querySelector('[data-slot="skeleton"]'),
+		).toBeInTheDocument();
+	});
+
 	it("renders the mean value with unit", () => {
 		mockData({ value: 23.5, unit: "%" });
 		render(<PrometheusMeanWidget widget={widget} refreshIntervalMs={60000} />);