refactor(core): align architecture with cordis spatiotemporal composability

backend/core/extpoints/schedule.go

@@ -32,6 +32,7 @@ type ScheduleExtension interface {
 	RegisterCron(spec string, taskType string, payload any, opts ...ScheduleOption)
 	Schedules() []ScheduleDefinition
 	Get(taskType string) (ScheduleDefinition, bool)
+	Unregister(taskType string) bool
 }
 
 // ScheduleRegistry collects and manages schedule registrations.
@@ -85,6 +86,25 @@ func (s *ScheduleRegistry) RegisterCron(spec string, taskType string, payload an
 	s.Register(spec, taskType, payload, opts...)
 }
 
+// Unregister removes a registered schedule definition by its task type.
+func (s *ScheduleRegistry) Unregister(taskType string) bool {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	if _, exists := s.lookup[taskType]; !exists {
+		return false
+	}
+
+	delete(s.lookup, taskType)
+	for i, item := range s.schedules {
+		if item.TaskType == taskType {
+			s.schedules = append(s.schedules[:i], s.schedules[i+1:]...)
+			break
+		}
+	}
+	return true
+}
+
 // Schedules returns a copy of all registered ScheduleDefinitions.
 func (s *ScheduleRegistry) Schedules() []ScheduleDefinition {
 	s.mu.RLock()