feat(creator-studio): pay toggle and entry in the publish settings card

The card below the writing surface only offered cover and scheduling, so
paid content could only be reached through the bottom bar's 发布 button.

- The card gains a 付费内容 row (rendered only with canPay): a toggle bound
  to draft.pay.enabled, a status line that reflects whether resources were
  added, and a 配置价格与付费资源 link.
- Turning the toggle on opens the publish drawer and scrolls it to the pay
  section, so pricing is the next thing the author sees. Entering from the
  bottom bar keeps the drawer at the top.

tests/widget-system/creator-studio-contract.test.cjs

@@ -429,6 +429,15 @@ test('writing surface is a centered paper card with a publish settings card belo
 	assert.match(settings, /type="datetime-local"/);
 	assert.match(settings, /canSchedule/);
 	assert.match(appSource, /scheduleEnabled=\{!!draft\.schedule\.enabled\}/);
+
+	// 付费开关在卡片里，且能直接打开发布抽屉的付费配置。
+	assert.match(settings, /canPay/);
+	assert.match(settings, /onPayEnabledChange/);
+	assert.match(settings, /onOpenPaySettings/);
+	assert.match(settings, /配置价格与付费资源/);
+	assert.match(appSource, /onOpenPaySettings=\{/);
+	assert.match(appSource, /focusPay=\{drawerFocusPay\}/);
+	assert.match(read('assets/creator-studio/src/panels/publish-drawer.tsx'), /scrollIntoView/);
 });
 
 test('scheduled publishing is validated and applied server side', () => {