feat: complete remaining Go backend modules

backend/internal/httpapi/httpapi_test.go

@@ -43,6 +43,44 @@ func TestHealthReportsProcessAndDatabaseConfigurationWithoutReadinessProbe(t *te
 	}
 }
 
+func TestHealthIncludesInjectedRuntimeCompatibilityDetails(t *testing.T) {
+	details := httpapi.HealthDetails{
+		VisualAPIMode: "volcengine",
+		EvolinkMode:   "mock",
+		SeedanceMode:  "seedance",
+		BailianMode:   "missing",
+		AuthMode:      "configured",
+		Capabilities: []any{
+			map[string]any{"id": "image.generate", "engine": "jimeng"},
+			map[string]any{"id": "video.generate", "engine": "seedance"},
+		},
+	}
+	recorder := httptest.NewRecorder()
+
+	httpapi.NewHandler(&readinessStub{}, httpapi.WithHealthDetails(details)).ServeHTTP(
+		recorder,
+		httptest.NewRequest(http.MethodGet, "/api/health", nil),
+	)
+
+	var response struct {
+		VisualAPIMode string           `json:"visualApiMode"`
+		EvolinkMode   string           `json:"evolinkMode"`
+		SeedanceMode  string           `json:"seedanceMode"`
+		BailianMode   string           `json:"bailianMode"`
+		AuthMode      string           `json:"authMode"`
+		Capabilities  []map[string]any `json:"capabilities"`
+	}
+	if err := json.NewDecoder(recorder.Body).Decode(&response); err != nil {
+		t.Fatalf("decode response: %v", err)
+	}
+	if response.VisualAPIMode != "volcengine" || response.EvolinkMode != "mock" || response.SeedanceMode != "seedance" || response.BailianMode != "missing" || response.AuthMode != "configured" {
+		t.Fatalf("runtime response = %+v", response)
+	}
+	if len(response.Capabilities) != 2 || response.Capabilities[0]["id"] != "image.generate" || response.Capabilities[1]["id"] != "video.generate" {
+		t.Fatalf("capabilities = %#v", response.Capabilities)
+	}
+}
+
 func TestReadyReportsSuccessfulDatabaseProbe(t *testing.T) {
 	readiness := &readinessStub{
 		status:      httpapi.DatabaseStatus{Backend: "postgres", Configured: true},