feat(agent): Agent 工作台 - 计划插话记忆、统一模型选择器并修复摘要与视频入库

将计划清单、运行中插话和个人记忆接入云端 Agent；全站模型选择器统一为左右二级菜单。画布摘要按预算截断不再整轮拒绝，首页视频未知宽高可入库。README 补充贡献者 morrow。

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/internal/model/models_agent_memory_setting.go

@@ -0,0 +1,34 @@
+package model
+
+import "time"
+
+const (
+	AgentMemoryCompactIntervalOff     = "off"
+	AgentMemoryCompactIntervalDaily   = "daily"
+	AgentMemoryCompactIntervalWeekly  = "weekly"
+	AgentMemoryCompactIntervalMonthly = "monthly"
+
+	AgentMemoryCompactStatusIdle      = "idle"
+	AgentMemoryCompactStatusQueued    = "queued"
+	AgentMemoryCompactStatusRunning   = "running"
+	AgentMemoryCompactStatusSucceeded = "succeeded"
+	AgentMemoryCompactStatusFailed    = "failed"
+)
+
+// AgentMemorySetting 是用户私有的记忆压缩偏好与最近一次压缩状态。
+type AgentMemorySetting struct {
+	UserID           string     `json:"userId" gorm:"primaryKey;size:36"`
+	CompactInterval  string     `json:"compactInterval" gorm:"size:16;index"`
+	LogicalModelID   string     `json:"logicalModelId" gorm:"size:36"`
+	ChannelID        string     `json:"channelId" gorm:"size:36"`
+	ChannelModelKey  string     `json:"channelModelKey" gorm:"size:160"`
+	Model            string     `json:"model" gorm:"size:240"`
+	LastCompactAt    *time.Time `json:"lastCompactAt,omitempty"`
+	CompactStartedAt *time.Time `json:"compactStartedAt,omitempty"`
+	CompactTaskID    string     `json:"compactTaskId,omitempty" gorm:"size:36;index"`
+	LastStatus       string     `json:"lastStatus" gorm:"size:16;index"`
+	LastSummaryJSON  string     `json:"-" gorm:"type:text"`
+	LastError        string     `json:"lastError,omitempty" gorm:"type:text"`
+	CreatedAt        time.Time  `json:"createdAt"`
+	UpdatedAt        time.Time  `json:"updatedAt"`
+}