Version: 0.9.66.dev.260504

后端：
1. 阶段 2 user/auth 服务边界落地，新增 `cmd/userauth` go-zero zrpc 服务、`services/userauth` 核心实现、gateway user API/zrpc client 与 shared contracts/ports，迁移注册、登录、刷新 token、登出、JWT、黑名单和 token 额度治理
2. gateway 与启动装配切流，`cmd/all` 只保留边缘路由、鉴权和轻量组合，通过 userauth zrpc 访问核心用户能力；拆分 MySQL/Redis 初始化与 AutoMigrate 边界，`userauth` 自迁 `users` 和 token 记账幂等表，`all` 不再迁用户表
3. 清退 Gin 单体旧 user/auth DAO、model、service、router、middleware 和 JWT handler，并同步调整 agent/schedule/cache/outbox 相关调用依赖
4. 补齐 refresh token 防并发重放、MySQL 幂等 token 记账、额度 `>=` 拦截和 RPC 错误映射，避免重复记账与内部错误透出

文档：
1. 新增《学习计划论坛与Token商店PRD》

backend/model/agent.go

@@ -255,22 +255,24 @@ type SSEMessageData struct {
 }
 
 type AgentChat struct {
-	ID                  int64      `gorm:"column:id;primaryKey;autoIncrement;comment:自增ID"`
-	ChatID              string     `gorm:"column:chat_id;type:varchar(36);not null;uniqueIndex:uk_chat_id;comment:会话UUID"`
-	UserID              int        `gorm:"column:user_id;not null;index:idx_user_last,priority:1;index:idx_user_status,priority:1;comment:所属用户ID"`
-	Title               *string    `gorm:"column:title;type:varchar(255);comment:会话标题"`
-	SystemPrompt        *string    `gorm:"column:system_prompt;type:text;comment:系统提示词"`
-	Model               *string    `gorm:"column:model;type:varchar(100);comment:模型标识"`
-	MessageCount        int        `gorm:"column:message_count;not null;default:0;comment:消息总数"`
-	TokensTotal         int        `gorm:"column:tokens_total;not null;default:0;comment:累计Token"`
-	LastMessageAt       *time.Time `gorm:"column:last_message_at;comment:最后消息时间"`
-	Status              string     `gorm:"column:status;type:varchar(32);not null;default:active;index:idx_user_status,priority:2;comment:会话状态"`
-	CompactionSummary   *string    `gorm:"column:compaction_summary;type:text;comment:历史上下文压缩摘要"`
-	CompactionWatermark int        `gorm:"column:compaction_watermark;not null;default:0;comment:压缩水位线（最后被压缩的消息ID）"`
-	ContextTokenStats   *string    `gorm:"column:context_token_stats;type:json;comment:上下文窗口实时token分布"`
-	CreatedAt           *time.Time `gorm:"column:created_at;autoCreateTime"`
-	UpdatedAt           *time.Time `gorm:"column:updated_at;autoUpdateTime"`
-	DeletedAt           *time.Time `gorm:"column:deleted_at;comment:软删除时间"`
+	ID                     int64      `gorm:"column:id;primaryKey;autoIncrement;comment:自增ID"`
+	ChatID                 string     `gorm:"column:chat_id;type:varchar(36);not null;uniqueIndex:uk_chat_id;comment:会话UUID"`
+	UserID                 int        `gorm:"column:user_id;not null;index:idx_user_last,priority:1;index:idx_user_status,priority:1;comment:所属用户ID"`
+	Title                  *string    `gorm:"column:title;type:varchar(255);comment:会话标题"`
+	SystemPrompt           *string    `gorm:"column:system_prompt;type:text;comment:系统提示词"`
+	Model                  *string    `gorm:"column:model;type:varchar(100);comment:模型标识"`
+	MessageCount           int        `gorm:"column:message_count;not null;default:0;comment:消息总数"`
+	TokensTotal            int        `gorm:"column:tokens_total;not null;default:0;comment:累计Token"`
+	LastHistoryEventID     *string    `gorm:"column:last_history_event_id;type:varchar(64);comment:最后一次聊天历史持久化事件ID"`
+	LastTokenAdjustEventID *string    `gorm:"column:last_token_adjust_event_id;type:varchar(64);comment:最后一次会话token调整事件ID"`
+	LastMessageAt          *time.Time `gorm:"column:last_message_at;comment:最后消息时间"`
+	Status                 string     `gorm:"column:status;type:varchar(32);not null;default:active;index:idx_user_status,priority:2;comment:会话状态"`
+	CompactionSummary      *string    `gorm:"column:compaction_summary;type:text;comment:历史上下文压缩摘要"`
+	CompactionWatermark    int        `gorm:"column:compaction_watermark;not null;default:0;comment:压缩水位线（最后被压缩的消息ID）"`
+	ContextTokenStats      *string    `gorm:"column:context_token_stats;type:json;comment:上下文窗口实时token分布"`
+	CreatedAt              *time.Time `gorm:"column:created_at;autoCreateTime"`
+	UpdatedAt              *time.Time `gorm:"column:updated_at;autoUpdateTime"`
+	DeletedAt              *time.Time `gorm:"column:deleted_at;comment:软删除时间"`
 }
 
 func (AgentChat) TableName() string { return "agent_chats" }
@@ -279,6 +281,7 @@ type ChatHistory struct {
 	ID                          int        `gorm:"column:id;primaryKey;autoIncrement"`
 	ChatID                      string     `gorm:"column:chat_id;type:varchar(36);not null;index:idx_user_chat,priority:2;index:idx_chat_id;comment:会话UUID"`
 	UserID                      int        `gorm:"column:user_id;not null;index:idx_user_chat,priority:1"`
+	SourceEventID               *string    `gorm:"column:source_event_id;type:varchar(64);uniqueIndex:uk_chat_history_source_event;comment:来源事件ID"`
 	MessageContent              *string    `gorm:"column:message_content;type:text;comment:消息内容"`
 	ReasoningContent            *string    `gorm:"column:reasoning_content;type:text;comment:deep reasoning text"`
 	ReasoningDurationSeconds    int        `gorm:"column:reasoning_duration_seconds;not null;default:0;comment:deep reasoning duration seconds"`