feat: 完善多模型配置与运行切换

将模型连接统一持久化管理，并支持 Agent 运行中切换模型以及中断后选择模型继续。补充配置校验、事务与前后端交互测试。

server/src/test/java/tech/easyflow/manuagent/agent/AgentExecutionServiceTest.java

@@ -1,14 +1,62 @@
 package tech.easyflow.manuagent.agent;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
 
+import com.fasterxml.jackson.databind.ObjectMapper;
+import io.agentscope.core.agui.adapter.AguiAgentAdapter;
+import java.util.UUID;
 import org.junit.jupiter.api.Test;
+import reactor.core.publisher.Flux;
+import reactor.core.publisher.Mono;
+import tech.easyflow.manuagent.project.ProjectFileService;
+import tech.easyflow.manuagent.project.ProjectService;
+import tech.easyflow.manuagent.skill.SkillService;
 
 /**
  * 验证 Agent 事件持久化的精简规则。
  */
 class AgentExecutionServiceTest {
 
+    /**
+     * Run 在创建时已经固化模型配置 ID；执行和模型重连都必须沿用该 ID，
+     * 不能在工厂内部重新读取可能已经变化的全局默认模型。
+     */
+    @Test
+    void shouldCreateAgentWithModelBoundToRun() {
+        UUID projectId = UUID.randomUUID();
+        UUID runId = UUID.randomUUID();
+        UUID modelId = UUID.randomUUID();
+        AgentFactory factory = mock(AgentFactory.class);
+        AgentFactory.AgentHandle handle = mock(AgentFactory.AgentHandle.class);
+        AguiAgentAdapter adapter = mock(AguiAgentAdapter.class);
+        SkillService skillService = mock(SkillService.class);
+        when(handle.adapter()).thenReturn(adapter);
+        when(adapter.run(any())).thenReturn(Flux.empty());
+        when(skillService.enabledNames()).thenReturn(new String[] {"document"});
+        when(factory.create(eq(projectId), eq(modelId), any(String[].class))).thenReturn(handle);
+
+        AgentExecutionService service = new AgentExecutionService(
+                new ObjectMapper(),
+                factory,
+                mock(AgentEventService.class),
+                mock(ProjectFileService.class),
+                skillService);
+        ProjectService.ProjectView project = mock(ProjectService.ProjectView.class);
+        when(project.id()).thenReturn(projectId);
+        when(project.threadId()).thenReturn("project-" + projectId);
+        AgentRunService.RunView run = new AgentRunService.RunView(
+                runId, projectId, modelId, "INITIAL", "RUNNING", null, null, null, null);
+
+        service.execute(project, run, "执行测试", Mono.never(), () -> { }, () -> false);
+
+        verify(factory).create(eq(projectId), eq(modelId), any(String[].class));
+    }
+
     /**
      * 验证文档视觉结果保留图片路径元数据并丢弃 Base64 正文。
      */