fix(taskrun): serialize RunRecord with snake_case json tags

The task run API was emitting PascalCase fields, so the client never saw status or error_message and treated every disconnect as a network error.

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

internal/taskrun/types.go

@@ -24,27 +24,29 @@ type CreateRequest struct {
 }
 
 // RunRecord 运行实例状态。
+// JSON 键与前端约定及 task_runs 列名一致；缺标签时 encoding/json 会输出 PascalCase，
+// 前端读 status/error_message 会得到 undefined，断线恢复分支全部失效。
 type RunRecord struct {
-	RunID              string
-	SessionID          string
-	ProjectID          int64
-	UserID             int64
-	ClientTurnID       string
-	IdempotencyKey     string // 新 run 稳定键；旧行保持 NULL 不参与唯一索引
-	TaskKey            string
-	Stage              string
-	WorkflowInstanceID int64
-	StageInstanceID    int64
-	WorkflowStageKey   string
-	Status             string // pending | running | completed | failed | cancelled | pending_author_confirmation | blocked_pending_governance | …
-	WorkspaceID        string
-	AssistantMsgID     int64
-	WorkerID           string
-	LeaseExpiresAt     *time.Time
-	CreatedAt          time.Time
-	UpdatedAt          time.Time
-	ErrorMessage       string
-	Attempt            int
+	RunID              string     `json:"run_id"`
+	SessionID          string     `json:"session_id"`
+	ProjectID          int64      `json:"project_id"`
+	UserID             int64      `json:"user_id"`
+	ClientTurnID       string     `json:"client_turn_id"`
+	IdempotencyKey     string     `json:"idempotency_key"`
+	TaskKey            string     `json:"task_key"`
+	Stage              string     `json:"stage"`
+	WorkflowInstanceID int64      `json:"workflow_instance_id"`
+	StageInstanceID    int64      `json:"stage_instance_id"`
+	WorkflowStageKey   string     `json:"workflow_stage_key"`
+	Status             string     `json:"status"` // pending | running | completed | failed | cancelled | pending_author_confirmation | blocked_pending_governance | …
+	WorkspaceID        string     `json:"workspace_id"`
+	AssistantMsgID     int64      `json:"assistant_message_id"`
+	WorkerID           string     `json:"worker_id"`
+	LeaseExpiresAt     *time.Time `json:"lease_expires_at"`
+	CreatedAt          time.Time  `json:"created_at"`
+	UpdatedAt          time.Time  `json:"updated_at"`
+	ErrorMessage       string     `json:"error_message"`
+	Attempt            int        `json:"attempt"`
 }
 
 // BuildTaskRunIdempotencyKey 新创建用稳定幂等键；空 client_turn 不设键。