fix: ACP NewSessionResponse 恢复返回 models 字段

67fdd4ca 那次合规审计误将 models 从响应里移除，但 SDK 0.19.2 的 schema 实际允许
models?: SessionModelState | null（标注 UNSTABLE 仅表示"未来可能变"，并非
"agent 禁止返回"）。标准 ACP 客户端（Cursor/Zed/VS Code/RCS）依赖此字段填充
模型选择器 —— 缺失会导致客户端 supportsModelSelection=false，模型切换 UI 不可用。

- createSessionMethod: return 里加回 models
- sessionLifecycle: getOrCreateSession 两处 return 透传 models（resume/load 路径）
- agent.test: 更新过时的 "models omitted for v1 compliance" 断言

Co-Authored-By: glm-5.2 <zai-org@claude-code-best.win>

src/services/acp/agent/sessionLifecycle.ts

@@ -79,6 +79,9 @@ async function getOrCreateSession(
       return {
         sessionId: params.sessionId,
         modes: existingSession.modes,
+        // Carry models over on reconnect so the client keeps its model selector
+        // populated (standard clients gate supportsModelSelection on this field).
+        models: existingSession.models,
         configOptions: existingSession.configOptions,
       }
     }
@@ -150,6 +153,8 @@ async function getOrCreateSession(
   return {
     sessionId: response.sessionId,
     modes: response.modes,
+    // createSession already returns models; pass it through. Same reason as above.
+    models: response.models,
     configOptions: response.configOptions,
   }
 }