修复终端首屏图表加载动画

frontend/components/dashboard/scan-terminal/TemperatureChartCanvas.tsx

@@ -89,7 +89,8 @@ function TemperatureChartSkeleton({ compact }: { compact: boolean }) {
             style={{ left: `${(index / Math.max(1, verticalLines - 1)) * 100}%` }}
           />
         ))}
-        <div className="absolute inset-x-10 top-1/3 h-10 rounded bg-slate-100/60" />
+        <div className="absolute inset-x-10 top-1/3 h-10 animate-pulse rounded bg-gradient-to-r from-slate-100 via-blue-100 to-slate-100" />
+        <div className="absolute inset-y-0 -left-1/3 w-1/3 animate-pulse bg-gradient-to-r from-transparent via-white/80 to-transparent" />
       </div>
     </div>
   );

frontend/components/dashboard/scan-terminal/__tests__/terminalGridPolicy.test.ts

@@ -101,9 +101,10 @@ export function runTests() {
     "terminal guide must describe the new 3x2 maximum layout instead of 3x3",
   );
   assert(
-    dashboardSource.includes("if (!cityInSlot || !rowForSlot)") &&
+    dashboardSource.includes("LoadingSlotCard") &&
+      dashboardSource.includes("cityInSlot && !rowForSlot && refreshing") &&
       dashboardSource.includes("handleSelectCityForSlot(slotIndex, null);"),
-    "stale saved chart slots must render the empty city picker instead of a row=null Temperature Chart",
+    "terminal must show a loading chart card for saved cities while the first scan rows are still loading, then fall back to the empty picker for stale slots",
   );
   assert(
     dashboardSource.includes("absolute left-1/2 top-12 z-50") &&
@@ -223,6 +224,12 @@ export function runTests() {
     }),
     "temperature chart should show the loading skeleton while the first detail fetch is in flight and no drawable data exists",
   );
+  assert(
+    chartCanvasSource.includes("animate-pulse") &&
+      chartCanvasSource.includes("Loading chart") &&
+      chartCanvasSource.includes("bg-gradient-to-r"),
+    "temperature chart loading skeleton must include visible animation on cold first-open charts",
+  );
   assert(
     !__shouldKeepTemperatureChartLoadingForTest({
       row: { city: "Moscow" } as any,