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

user-frontend/src/App.vue

@@ -19,4 +19,20 @@
 .el-button--primary { --el-button-bg-color: #1890ff; --el-button-border-color: #1890ff; --el-button-hover-bg-color: #40a9ff; --el-button-hover-border-color: #40a9ff; --el-button-active-bg-color: #096dd9; --el-button-active-border-color: #096dd9; }
 .el-tag--primary { --el-tag-bg-color: #e6f7ff; --el-tag-border-color: #91d5ff; --el-tag-text-color: #1890ff; }
 a { color: #1890ff; }
+
+.el-table { width: 100%; }
+.el-table__body-wrapper { overflow-x: auto; }
+
+@media (max-width: 768px) {
+  .el-dialog { width: calc(100% - 20px) !important; max-width: 100% !important; }
+  .el-dialog__body { padding: 16px !important; }
+  .el-form-item { margin-bottom: 14px !important; }
+  .el-card__body { padding: 16px !important; }
+  .el-tabs__content { padding: 0 !important; }
+  .el-table { font-size: 12px; }
+  .el-table .cell { padding-left: 6px !important; padding-right: 6px !important; }
+  .el-empty { padding: 20px 0 !important; }
+  [class*="el-col-"] { margin-bottom: 12px; }
+  .el-row--flex { flex-wrap: wrap; }
+}
 </style>