Add landing page, referral system, usage quotas, search API management, and yearly pricing

- Separate workspace landing from login for better UX
- Referral system rewards both parties with Pro days
- Quota enforcement prevents abuse without breaking endpoints
- 7-day free trial with auto-downgrade on expiry
- Admin-managed search provider config (SearXNG, Bing)
- 15% discount on annual subscriptions
- MCP search server wrapping opencode search
- Fix discovery module field name mismatch causing 422

backend/app/services/payment.py

@@ -14,12 +14,16 @@ logger = logging.getLogger(__name__)
 PLANS = {
     "free": {"price": 0, "duration_days": None},
     "pro": {"price": 99, "duration_days": 30},
+    "pro_yearly": {"price": 999, "duration_days": 365},
     "enterprise": {"price": 399, "duration_days": 30},
+    "enterprise_yearly": {"price": 3999, "duration_days": 365},
 }
 
 PLAN_DESCRIPTIONS = {
     "pro": "TradeMate Pro 版会员",
+    "pro_yearly": "TradeMate Pro 版会员（年付）",
     "enterprise": "TradeMate 企业版会员",
+    "enterprise_yearly": "TradeMate 企业版会员（年付）",
 }
 
 
@@ -41,6 +45,7 @@ class PaymentService:
                     "id": "free",
                     "name": "免费版",
                     "price": 0,
+                    "period": "month",
                     "features": [
                         "1 个产品",
                         "20 次翻译/天",
@@ -52,6 +57,7 @@ class PaymentService:
                     "id": "pro",
                     "name": "Pro 版",
                     "price": 99,
+                    "period": "month",
                     "features": [
                         "10 个产品",
                         "无限翻译",
@@ -60,19 +66,52 @@ class PaymentService:
                         "报价单生成",
                     ],
                 },
+                {
+                    "id": "pro_yearly",
+                    "name": "Pro 版（年付）",
+                    "price": 999,
+                    "period": "year",
+                    "original_price": 1188,
+                    "features": [
+                        "10 个产品",
+                        "无限翻译",
+                        "50 个客户",
+                        "跟进提醒",
+                        "报价单生成",
+                        "省 ¥189",
+                    ],
+                },
                 {
                     "id": "enterprise",
                     "name": "企业版",
                     "price": 399,
+                    "period": "month",
                     "features": [
-                        "无限产品",
-                        "多人协作",
+                        "无限产品/客户",
+                        "团队协作",
                         "品牌报价单",
                         "专属语料训练",
                         "API 接入",
+                        "优先支持",
                     ],
                 },
-            ]
+                {
+                    "id": "enterprise_yearly",
+                    "name": "企业版（年付）",
+                    "price": 3999,
+                    "period": "year",
+                    "original_price": 4788,
+                    "features": [
+                        "无限产品/客户",
+                        "团队协作",
+                        "品牌报价单",
+                        "专属语料训练",
+                        "API 接入",
+                        "优先支持",
+                        "省 ¥789",
+                    ],
+                },
+            ],
         }
 
     async def get_current_subscription(self, user_id: str) -> Dict[str, Any]: