Manager: properly set task.JobUUID and task.WorkerUUID when using GORM

Add a GORM hook that sets `task.JobUUID` and `.WorkerUUID`. These were
only set by the sqlc code; this change ensures that they are now always
set, so that the caller doesn't have to worry about which function is
already ported to sqlc and which one is still GORM.

internal/manager/persistence/jobs.go

@@ -65,14 +65,14 @@ type Task struct {
 	Type     string         `gorm:"type:varchar(32);default:''"`
 	JobID    uint           `gorm:"default:0"`
 	Job      *Job           `gorm:"foreignkey:JobID;references:ID;constraint:OnDelete:CASCADE"`
-	JobUUID  string         `gorm:"-"` // Fetched by SQLC, not GORM.
+	JobUUID  string         `gorm:"-"` // Fetched by SQLC, handled by GORM in Task.AfterFind()
 	Priority int            `gorm:"type:smallint;default:50"`
 	Status   api.TaskStatus `gorm:"type:varchar(16);default:''"`
 
 	// Which worker is/was working on this.
 	WorkerID      *uint
 	Worker        *Worker   `gorm:"foreignkey:WorkerID;references:ID;constraint:OnDelete:SET NULL"`
-	WorkerUUID    string    `gorm:"-"`     // Fetched by SQLC, not GORM.
+	WorkerUUID    string    `gorm:"-"`     // Fetched by SQLC, handled by GORM in Task.AfterFind()
 	LastTouchedAt time.Time `gorm:"index"` // Should contain UTC timestamps.
 
 	// Dependencies are tasks that need to be completed before this one can run.
@@ -82,6 +82,17 @@ type Task struct {
 	Activity string   `gorm:"type:varchar(255);default:''"`
 }
 
+// AfterFind updates the task JobUUID and WorkerUUID fields from its job/worker, if known.
+func (t *Task) AfterFind(tx *gorm.DB) error {
+	if t.JobUUID == "" && t.Job != nil {
+		t.JobUUID = t.Job.UUID
+	}
+	if t.WorkerUUID == "" && t.Worker != nil {
+		t.WorkerUUID = t.Worker.UUID
+	}
+	return nil
+}
+
 type Commands []Command
 
 type Command struct {