fix(a11y): correct duplicate aria-labels in CostPage sections

Author: OneStepAt4time

dashboard/src/pages/CostPage.tsx

@@ -395,7 +395,7 @@ export default function CostPage() {
       {modelData.length > 0 && (
         <div className="grid grid-cols-1 gap-4 lg:grid-cols-2">
           {/* Pie chart */}
-          <section className="rounded-lg border border-[var(--color-border-strong)] bg-[var(--color-surface-strong)] p-5" aria-label="Daily spend chart">
+          <section className="rounded-lg border border-[var(--color-border-strong)] bg-[var(--color-surface-strong)] p-5" aria-label="Cost by model chart">
             <h3 className="mb-4 text-lg font-medium text-[var(--color-text-primary)]">
               Cost by Model
             </h3>
@@ -426,7 +426,7 @@ export default function CostPage() {
           </section>
 
           {/* Model list */}
-          <section className="rounded-lg border border-[var(--color-border-strong)] bg-[var(--color-surface-strong)] p-5" aria-label="Daily spend chart">
+          <section className="rounded-lg border border-[var(--color-border-strong)] bg-[var(--color-surface-strong)] p-5" aria-label="Model details">
             <h3 className="mb-4 text-lg font-medium text-[var(--color-text-primary)]">
               Model Details
             </h3>