feat: target workflow runs by tag selector

server/internal/models/workflow.go

@@ -50,6 +50,7 @@ type Workflow struct {
 	WorkflowID      string            `bson:"workflow_id" json:"workflow_id"`
 	Name            string            `bson:"name" json:"name"`
 	TargetServerIDs []string          `bson:"target_server_ids" json:"target_server_ids"`
+	TargetTags      map[string]string `bson:"target_tags,omitempty" json:"target_tags,omitempty"`
 	Steps           []WorkflowStepRef `bson:"steps" json:"steps"`
 	CreatedAt       time.Time         `bson:"created_at" json:"created_at"`
 	UpdatedAt       time.Time         `bson:"updated_at" json:"updated_at"`