feat(config): default to WebSocket and migrate saved HTTP settings

apps/showcase_ui/src/app/components/model-settings/model-settings.component.spec.ts

@@ -30,29 +30,29 @@ describe('持久化模型与功能设置', () => {
     http.expectNone('/api/system/model-settings');
   }));
 
-  it('加载、测试和保存 WebSocket 选择，旧配置默认 HTTP', fakeAsync(() => {
+  it('缺少协议的配置默认 WebSocket，允许手动切回 HTTP', fakeAsync(() => {
     const fixture = TestBed.createComponent(ModelSettingsComponent);
     fixture.detectChanges();
     http.expectOne('/api/system/model-settings').flush(config);
     tick();
     fixture.detectChanges();
     const component = fixture.componentInstance;
-    expect(component.transport).toBe('http');
+    expect(component.transport).toBe('websocket');
     const selector: HTMLSelectElement = fixture.nativeElement.querySelector('#model-transport');
-    selector.value = 'websocket';
+    selector.value = 'http';
     selector.dispatchEvent(new Event('change'));
     tick();
     fixture.detectChanges();
     component.test();
     const check = http.expectOne('/api/system/model-settings/test');
-    expect(check.request.body.transport).toBe('websocket');
-    check.flush({message: 'Responses WEBSOCKET 连接测试成功'});
+    expect(check.request.body.transport).toBe('http');
+    check.flush({message: 'Responses HTTP 连接测试成功'});
     component.save();
     const save = http.expectOne('/api/system/model-settings');
-    expect(save.request.body.transport).toBe('websocket');
+    expect(save.request.body.transport).toBe('http');
     expect(save.request.body.api_key).toBeUndefined();
-    save.flush({...config, transport: 'websocket'});
-    expect(component.transport).toBe('websocket');
+    save.flush({...config, transport: 'http'});
+    expect(component.transport).toBe('http');
   }));
 
   it('加载配置后保留密钥，保存新模型且不发送空密钥', () => {

apps/showcase_ui/src/app/components/model-settings/model-settings.component.ts

@@ -109,7 +109,7 @@ interface ModelSettings {
   `]
 })
 export class ModelSettingsComponent implements OnInit {
-  transport: 'http' | 'websocket' = 'http';
+  transport: 'http' | 'websocket' = 'websocket';
   readonly reasoningValues = REASONING_VALUES;
   readonly reasoningLabels = REASONING_LABELS;
   private http = inject(HttpClient);
@@ -144,7 +144,7 @@ export class ModelSettingsComponent implements OnInit {
   }
   private apply(config: ModelSettings): void {
     this.baseUrl = config.base_url; this.model = config.model; this.timeout = config.timeout_seconds;
-    this.transport = config.transport ?? 'http';
+    this.transport = config.transport ?? 'websocket';
     this.modelPresets = config.model_presets;
     this.retries = config.max_retries; this.retryInterval = config.retry_interval_seconds ?? 10; this.reasoning = config.reasoning_effort ?? 'high'; this.keyConfigured.set(config.api_key_configured); this.envPath.set(config.env_path);
     this.rateLimitRetry = config.rate_limit_retry_seconds ?? 60;