fix(ai): correct double-wrap in OCR engine endpoints causing e.map error

Controller was returning { data: engines } which TransformInterceptor
wrapped again into { data: { data: engines } }. extractData() only peeled
one layer, leaving an object instead of the array — causing .map() to fail
in OcrEngineSelector.

- Return data directly from getOcrEngines() and selectOcrEngine()
- Add Array.isArray guard in OcrEngineSelector as defensive layer

backend/src/modules/ai/ai.controller.ts

@@ -1041,12 +1041,11 @@ export class AiController {
   @ApiOperation({
     summary: 'OCR Engines — ดึงรายการเอนจิน OCR ทั้งหมดที่มีในระบบ (T003)',
   })
-  async getOcrEngines(): Promise<{ data: OcrEngineResponseDto[] }> {
+  async getOcrEngines(): Promise<OcrEngineResponseDto[]> {
     if (!this.ocrService) {
       throw new SystemException('OcrService not injected in AiController');
     }
-    const engines = await this.ocrService.getOcrEngines();
-    return { data: engines };
+    return this.ocrService.getOcrEngines();
   }
 
   @Post('ocr-engines/:engineId/select')
@@ -1064,14 +1063,10 @@ export class AiController {
   async selectOcrEngine(
     @Param('engineId', ParseUuidPipe) engineId: string,
     @CurrentUser() user: User
-  ): Promise<{ data: OcrEngineConfiguration }> {
+  ): Promise<OcrEngineConfiguration> {
     if (!this.ocrService) {
       throw new SystemException('OcrService not injected in AiController');
     }
-    const engine = await this.ocrService.selectOcrEngine(
-      engineId,
-      user.user_id
-    );
-    return { data: engine };
+    return this.ocrService.selectOcrEngine(engineId, user.user_id);
   }
 }

frontend/components/admin/ai/OcrEngineSelector.tsx

@@ -22,7 +22,7 @@ export default function OcrEngineSelector() {
     try {
       setIsLoading(true);
       const data = await adminAiService.getOcrEngines();
-      setEngines(data);
+      setEngines(Array.isArray(data) ? data : []);
     } catch (_err: unknown) {
       toast.error('ไม่สามารถดึงข้อมูล OCR Engines ได้');
     } finally {