fix: address usage billing review feedback

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: asizikov

src/components/ui/BillingTotalsCards.test.ts

@@ -48,4 +48,16 @@ describe('BillingTotalsCards', () => {
     expect(html).toContain(EXISTING_DISCOUNT_DISCLAIMER)
     expect(html).not.toContain('Promotional amounts are used in this simulation.')
   })
+
+  it('formats included discount rows with a single explicit minus sign', () => {
+    const html = renderToStaticMarkup(createElement(BillingTotalsCards, {
+      ...BASE_PROPS,
+      pruDiscountAmount: -1,
+      aicDiscountAmount: -2.34,
+    }))
+
+    expect(html).toContain('−$1.00')
+    expect(html).toContain('−$2.34')
+    expect(html).not.toContain('−$-')
+  })
 })

src/components/ui/BillingTotalsCards.tsx

@@ -85,7 +85,7 @@ export function BillingTotalsCards({
               </div>
               <div className="flex justify-between items-center text-[13px] text-fg-muted tabular-nums">
                 <span>Included PRUs</span>
-                <span>−{formatUsd(pruDiscountAmount)}</span>
+                <span>−{formatUsd(Math.abs(pruDiscountAmount))}</span>
               </div>
               <div className="pt-[6px] border-t border-dotted border-border-muted flex flex-col gap-[6px]">
                 <div className="flex justify-between items-center text-[13px] text-fg-default tabular-nums">
@@ -125,7 +125,7 @@ export function BillingTotalsCards({
             </div>
             <div className="flex justify-between items-center text-[13px] text-fg-muted tabular-nums">
               <span>Included AICs</span>
-              <span>−{formatUsd(aicDiscountAmount)}</span>
+              <span>−{formatUsd(Math.abs(aicDiscountAmount))}</span>
             </div>
             <div className="pt-[6px] border-t border-dotted border-border-muted flex flex-col gap-[6px]">
               <div className="flex justify-between items-center text-[13px] text-fg-default tabular-nums">

src/views/ModelsView.tsx

@@ -279,7 +279,7 @@ export function ModelsView({
             </>
           )}
           <DualAxisLineChart
-            title={`Daily AI Credits gross cost (${selectedModel})`}
+            title={`Daily AI Credits gross and net cost (${selectedModel})`}
             labels={filledPerModelDailyData.map((day) => day.date)}
             series={[
               {

src/views/UserDetailsView.tsx

@@ -304,7 +304,7 @@ export function UserDetailsView({
                   {!isNativeAiCredits && <th className={thNum}>PRUs</th>}
                   <th className={thNum}>AICs</th>
                   {isNativeAiCredits && <th className={thNum}>AIC Gross Cost</th>}
-                  {isNativeAiCredits && <th className={thNum}>Included AICs</th>}
+                  {isNativeAiCredits && <th className={thNum}>Included Discount</th>}
                   {!isNativeAiCredits && <th className={thNum}>PRU Net Cost</th>}
                   <th className={thNum}>AIC Net Cost</th>
                   {!isNativeAiCredits && <th className={thNum}>Difference</th>}
@@ -326,7 +326,7 @@ export function UserDetailsView({
                         {!isNativeAiCredits && <td className={tdNum}>{formatInt(row.requests)}</td>}
                         <td className={tdNum}>{formatAic(row.aicQuantity)}</td>
                         {isNativeAiCredits && <td className={tdNum}>{formatCost(row.aicGrossAmount)}</td>}
-                        {isNativeAiCredits && <td className={tdNum}>−{formatCost(row.aicDiscountAmount)}</td>}
+                        {isNativeAiCredits && <td className={tdNum}>−{formatCost(Math.abs(row.aicDiscountAmount))}</td>}
                         {!isNativeAiCredits && <td className={tdNum}>{formatCost(row.netAmount)}</td>}
                         <td className={tdNum}>{formatCost(row.aicNetAmount)}</td>
                         {!isNativeAiCredits && (