fix: populate UserID in dispatch.go and remove omitempty from actor_id

Agent-Logs-Url: https://github.com/Paca-AI/plugin-sdk-go/sessions/244e47a5-a8a9-4aff-bedf-a6e4d5fcab1b

Co-authored-by: pikann <41873019+pikann@users.noreply.github.com>

Author: Copilot

dispatch.go

@@ -45,6 +45,7 @@ func (d *dispatcher) handleRequest(payload []byte) []byte {
 		Query      map[string]string `json:"query"`
 		ProjectID  string            `json:"project_id"`
 		CallerID   string            `json:"caller_id"`
+		UserID     string            `json:"user_id"`
 		CallerRole string            `json:"caller_role"`
 		Headers    map[string]string `json:"headers"`
 		Body       []byte            `json:"body"`
@@ -70,6 +71,7 @@ func (d *dispatcher) handleRequest(payload []byte) []byte {
 		Body:       hr.Body,
 		Caller: CallerIdentity{
 			CallerID:   hr.CallerID,
+			UserID:     hr.UserID,
 			CallerRole: hr.CallerRole,
 			ProjectID:  hr.ProjectID,
 		},

wasm_backends.go

@@ -185,7 +185,7 @@ func EmitEvent(topic string, payload any) {
 type activityInput struct {
 	TaskID       string `json:"task_id"`
 	ProjectID    string `json:"project_id"`
-	ActorID      string `json:"actor_id,omitempty"`
+	ActorID      string `json:"actor_id"`
 	ActivityType string `json:"activity_type"`
 	Content      any    `json:"content"`
 }