Add AI job stage metrics

internal/model/job.go

@@ -119,6 +119,16 @@ type ErrorStat struct {
 	Last24h      int64  `json:"last_24h"`
 }
 
+type StageStat struct {
+	OwnerService       string `json:"owner_service"`
+	TaskType           string `json:"task_type"`
+	ModelProfile       string `json:"model_profile"`
+	Done24h            int64  `json:"done_24h"`
+	AvgDurationSeconds int64  `json:"avg_duration_seconds"`
+	AvgAttempts        int64  `json:"avg_attempts"`
+	Retried24h         int64  `json:"retried_24h"`
+}
+
 type OwnerStat struct {
 	OwnerService string `json:"owner_service"`
 	TaskType     string `json:"task_type"`
@@ -132,4 +142,5 @@ type Stats struct {
 	Queues []QueueStat `json:"queues"`
 	Owners []OwnerStat `json:"owners,omitempty"`
 	Errors []ErrorStat `json:"errors,omitempty"`
+	Stages []StageStat `json:"stages,omitempty"`
 }