♻️ refactor(InvitationCard): restructure cards with title prop and clean up styling

- Move card titles (earnings, total revenue, invitations) to Card title prop for consistency
- Remove custom color classes in favor of Semi-UI's built-in type system
- Standardize Text component usage with strong and tertiary types
- Improve code maintainability and visual consistency across all cards
- Align structure with existing reward description card pattern

web/src/i18n/locales/en.json

@@ -855,7 +855,6 @@
   "邀请人数": "Number of people invited",
   "兑换码充值": "Redemption code recharge",
   "奖励说明": "Reward description",
-  "人": "",
   "选择支付方式": "Select payment method",
   "处理中": "Processing",
   "账户充值": "Account recharge",