3D 提交地址改成按 endpoint 穷尽映射

- src/services/image-editor/editorProjectClient.ts：新增 EDITOR_MODEL3D_ENDPOINT_API（Record<Model3dPricingEndpoint, string>）取代三元判断；原写法对非 image-to-model 的值一律回落 text-to-model，endpoint 联合扩容时会静默走错接口

验证：npx tsc -p tsconfig.typecheck-guardrails.json --noEmit

src/services/image-editor/editorProjectClient.ts

@@ -721,6 +721,12 @@ export type EditorGenerationModelPricing = {
 
 export type Model3dPricingEndpoint = 'text-to-model' | 'image-to-model';
 
+/** endpoint 到提交地址的穷尽映射：新增 endpoint 时这里会缺键并报编译错误。 */
+const EDITOR_MODEL3D_ENDPOINT_API: Record<Model3dPricingEndpoint, string> = {
+  'text-to-model': EDITOR_MODEL3D_TEXT_TO_MODEL_API,
+  'image-to-model': EDITOR_MODEL3D_IMAGE_TO_MODEL_API,
+};
+
 export type Model3dAddOnPriceKey =
   | 'hdTexture'
   | 'ultraTexture'
@@ -1740,9 +1746,7 @@ export async function submitModel3dGenerationRequest({
   idempotencyKey: string;
 }) {
   return requestJson<Model3dGenerationSubmissionResponse>(
-    endpoint === 'image-to-model'
-      ? EDITOR_MODEL3D_IMAGE_TO_MODEL_API
-      : EDITOR_MODEL3D_TEXT_TO_MODEL_API,
+    EDITOR_MODEL3D_ENDPOINT_API[endpoint],
     {
       method: 'POST',
       headers: {