feat: 添加视觉设计语言系统并重构认证页面UI

- 新增 visual_design_language.md 设计规范文档
- 新增 auth 设计 tokens (authBackground, authCard, authInput, feedback 系列等)
- 重构登录/注册/验证码/重置密码页面为新设计系统
- 新增 AuthHeroHeader, AuthSurfaceCard, AuthSection, AuthField, PasswordField 组件
- 重构 AppBanner 和 Toast 支持多类型配置 (info/success/warning/error)
- 后端 AgentScope: 重整 schemas/prompts/tools 作用域, 新增协议文档
- 更新 AGENTS.md 集成视觉设计语言约束

docs/protocols/invite-codes.md

@@ -0,0 +1,53 @@
+# Invite Codes Protocol
+
+> **NOTE**: This document is the single source of truth. All implementations must follow this specification.
+
+## Overview
+
+Invite codes for referral system with reward configuration.
+
+## Version
+
+- **Current**: `1.0`
+- **Status**: Active
+
+---
+
+## Reward Configuration
+
+```typescript
+interface InviteCodeRewardConfig {
+  // Reserved for future use
+  // Currently unused, allowing custom extensions
+  [key: string]: any;
+}
+```
+
+---
+
+## Database Field
+
+| Field | Type | Description |
+|-------|------|-------------|
+| reward_config | jsonb | Reward configuration for invite codes |
+
+---
+
+## JSON Examples
+
+### Empty Config
+
+```json
+{}
+```
+
+### Future Usage Example
+
+```json
+{
+  "reward_type": "credits",
+  "reward_amount": 100,
+  "currency": "USD",
+  "max_rewards_per_user": 5
+}
+```