feat(ai): implement AI models management and configuration in admin panel

backend/src/receipt-import/receipt-import.service.ts

@@ -11,6 +11,7 @@ import { AiService } from '../ai/ai.service';
 import { CategoriesService } from '../categories/categories.service';
 
 const MISTRAL_API_URL = 'https://api.mistral.ai/v1/chat/completions';
+export const RECEIPT_IMPORT_MODEL = 'mistral-tiny-2603';
 
 const IMAGE_PROMPT = `Du är en kvittoläsare. Analysera detta kvitto och returnera ENDAST en JSON-array med alla köpta varor.
 Varje vara ska ha följande fält:
@@ -78,7 +79,7 @@ export class ReceiptImportService {
         Authorization: `Bearer ${apiKey}`,
       },
       body: JSON.stringify({
-        model: 'pixtral-12b-2409',
+        model: RECEIPT_IMPORT_MODEL,
         messages: [
           {
             role: 'user',
@@ -126,7 +127,7 @@ export class ReceiptImportService {
         Authorization: `Bearer ${apiKey}`,
       },
       body: JSON.stringify({
-        model: 'mistral-small-latest',
+        model: RECEIPT_IMPORT_MODEL,
         messages: [{ role: 'user', content: TEXT_PROMPT(pdfText) }],
         max_tokens: 2000,
         temperature: 0.1,