feat: add supplier scoring and UPC file analysis functionality

- Implemented supplier scoring logic in `supplier-scoring.ts` with functions to compute demand score, competition penalty, and overall supplier product score.
- Created unit tests for supplier scoring in `supplier-scoring.test.ts` to validate scoring logic against various scenarios.
- Developed UPC file analysis tool in `upc-file-analysis.ts` to process UPCs in batches, fetch product data from Keepa and SP-API, and generate supplier results.
- Added UPC input reading functionality in `upc-file-reader.ts` to handle XLSX and XLS files, including validation for UPC formats.
- Introduced a command-line tool in `upc-lookup.ts` for looking up UPCs and displaying detailed results or mappings to ASINs.
- Enhanced error handling and logging throughout the new modules for better traceability and user feedback.

src/server.ts

@@ -5,10 +5,10 @@ import {
   fetchKeepaDataBatch,
   lookupKeepaUpcs,
   mapUpcsToAsins,
-} from "./keepa.ts";
-import { runUpcFileAnalysis } from "./upc-file-analysis.ts";
-import { fetchSellabilityBatch, fetchSpApiPricingAndFees } from "./sp-api.ts";
-import { analyzeProducts } from "./llm.ts";
+} from "./integrations/keepa.ts";
+import { runUpcFileAnalysis } from "./supplier/upc-file-analysis.ts";
+import { fetchSellabilityBatch, fetchSpApiPricingAndFees } from "./integrations/sp-api.ts";
+import { analyzeProducts } from "./integrations/llm.ts";
 import type {
   EnrichedProduct,
   KeepaUpcLookupDetail,