refactor(*): 平台架构 - 拆分后端领域模块与画布前端组件并补充测试

backend/internal/app/cloud_agent_pi_contract_test.go

@@ -9,9 +9,13 @@ import (
 
 func TestCloudAgentProductionSchedulingDoesNotCallLegacyGoLoop(t *testing.T) {
 	root := filepath.Join("..", "..")
+	// 生产调度入口：Agent 创建、运行时（含拆分出的调度/工具/媒体文件）与任务 worker。
+	// 调度循环本身（cloud_agent_runtime_scheduler.go）定义了旧入口，只检查调用方。
 	files := []string{
 		filepath.Join(root, "internal", "app", "cloud_agent.go"),
 		filepath.Join(root, "internal", "app", "cloud_agent_runtime.go"),
+		filepath.Join(root, "internal", "app", "cloud_agent_runtime_media.go"),
+		filepath.Join(root, "internal", "app", "cloud_agent_runtime_tools.go"),
 		filepath.Join(root, "internal", "app", "task_worker.go"),
 	}
 	for _, file := range files {
@@ -33,11 +37,16 @@ func TestCloudAgentProductionSchedulingDoesNotCallLegacyGoLoop(t *testing.T) {
 
 func TestCloudAgentPiRuntimeContractUsesGovernedStepBridge(t *testing.T) {
 	root := filepath.Join("..", "..")
-	coordinator, err := os.ReadFile(filepath.Join(root, "internal", "app", "cloud_agent_pi_coordinator.go"))
-	if err != nil {
-		t.Fatal(err)
+	// 协调器拆分为协调、请求组装、模型桥与消息/工具桥四个文件，合同覆盖整组。
+	var coordinator strings.Builder
+	for _, name := range []string{"cloud_agent_pi_coordinator.go", "cloud_agent_pi_request.go", "cloud_agent_pi_model.go", "cloud_agent_pi_bridge.go"} {
+		body, err := os.ReadFile(filepath.Join(root, "internal", "app", name))
+		if err != nil {
+			t.Fatal(err)
+		}
+		coordinator.Write(body)
 	}
-	text := string(coordinator)
+	text := coordinator.String()
 	for _, required := range []string{
 		"Operation: cloudAgentStepOperation",
 		"s.enqueueCloudAgentTask(run, &state, req, nil)",