修复(充值弹层): max 档不再提示可补差升档

- 状态卡原先无条件显示「可同周期补差升档」，已是最高档时并无更高档位可升
- 父组件按启用目录计算 hasUpgradePath（存在 rank 更高的档位），无升级路径时只保留「周期切换需等到期后」
- 补 max 档与 plus 档的对照断言

packages/shared/src/components/PlatformProfileRechargeModal/index.test.tsx

@@ -291,6 +291,7 @@ describe('PlatformProfileRechargeModal', () => {
       screen.getByRole('button', { name: 'Plus 年付 当前套餐' }),
     ).toHaveProperty('disabled', true);
     expect(screen.getByText('当前 Plus · 年付')).toBeTruthy();
+    expect(screen.getAllByText(/可同周期补差升档/).length).toBeGreaterThan(0);
 
     await user.click(screen.getByRole('button', { name: 'Max 年付 补差升级' }));
 
@@ -307,6 +308,39 @@ describe('PlatformProfileRechargeModal', () => {
     expect(onSubmitMembershipCheckout).toHaveBeenCalledWith('max', 'yearly');
   });
 
+  test('已是最高的 max 档不再提示可补差升档', () => {
+    render(
+      <PlatformProfileRechargeModal
+        center={{
+          mudPointBalance: buildMudPointBalance(8_650),
+          membership: buildActiveMembership('max', 'yearly'),
+          pointProducts: buildPointProducts(),
+          membershipPlans: [STARTER_PLAN, PLUS_PLAN, MAX_PLAN],
+          latestOrder: null,
+          hasPointsRecharged: true,
+        }}
+        isLoading={false}
+        error={null}
+        submittingProductId={null}
+        nativePayment={null}
+        membershipQuote={null}
+        isLoadingMembershipQuote={false}
+        membershipQuoteError={null}
+        onClose={vi.fn()}
+        onRetry={vi.fn()}
+        onBuy={vi.fn()}
+        onRequestMembershipQuote={vi.fn()}
+        onSubmitMembershipCheckout={vi.fn()}
+        onConfirmNativePayment={vi.fn()}
+        onCloseNativePayment={vi.fn()}
+      />,
+    );
+
+    expect(screen.getByText('当前 Max · 年付')).toBeTruthy();
+    expect(screen.queryByText(/可同周期补差升档/)).toBeNull();
+    expect(screen.getByText('周期切换需等到期后')).toBeTruthy();
+  });
+
   test('keeps an active member as member when their current plan is disabled', async () => {
     const user = userEvent.setup();
     const onRequestMembershipQuote = vi.fn();

packages/shared/src/components/PlatformProfileRechargeModal/index.tsx

@@ -594,9 +594,12 @@ function PlatformRechargeTabNav({
 function PlatformMembershipStatusCard({
   membership,
   currentPlan,
+  hasUpgradePath,
 }: {
   membership: ProfileMembership;
   currentPlan: ProfileMembershipPlanRecord | null;
+  /** 是否存在更高档位可补差升级；已是最高的 max 档时为 false。 */
+  hasUpgradePath: boolean;
 }) {
   const planTitle = currentPlan?.title ?? '会员';
   const cycleLabel = membership.cycleKind === 'yearly' ? '年付' : '月付';
@@ -620,9 +623,15 @@ function PlatformMembershipStatusCard({
         </div>
       </div>
       <div className="shrink-0 text-right text-[10px] font-semibold text-[var(--platform-text-soft)]">
-        可同周期补差升档
-        <br />
-        周期切换需等到期后
+        {hasUpgradePath ? (
+          <>
+            可同周期补差升档
+            <br />
+            周期切换需等到期后
+          </>
+        ) : (
+          '周期切换需等到期后'
+        )}
       </div>
     </div>
   );
@@ -1362,6 +1371,13 @@ export function PlatformProfileRechargeModal({
       ) ?? null,
     [center?.membershipPlans, membership?.plan],
   );
+  // 已是最高的 max 档时没有可升级目标，状态卡不应再提示「可同周期补差升档」。
+  const hasUpgradePath = useMemo(
+    () =>
+      currentPlanRecord !== null &&
+      membershipPlans.some((plan) => plan.rank > currentPlanRecord.rank),
+    [currentPlanRecord, membershipPlans],
+  );
   const [activeTab, setActiveTab] =
     useState<PlatformProfileRechargeTab>('subscription');
   const [cycleKind, setCycleKind] =
@@ -1488,6 +1504,7 @@ export function PlatformProfileRechargeModal({
                 <PlatformMembershipStatusCard
                   membership={membership}
                   currentPlan={currentPlanRecord}
+                  hasUpgradePath={hasUpgradePath}
                 />
               ) : null}
               <PlatformMembershipCycleSwitch