feat: add ASIN offer search functionality

- Introduced a new script `asin-offer-search.ts` for searching product offers by ASIN.
- Updated `package.json` to include a new command for the ASIN offer search.
- Enhanced configuration in `config.ts` to support SearXNG URL and timeout settings.
- Added comprehensive tests for the new search functionality in `searxng.test.ts`.
- Implemented the core search logic in `searxng.ts`, supporting multiple providers and price detection.

package.json

@@ -8,6 +8,7 @@
     "monthly-sold": "bun run src/top-monthly-sold-by-category.ts",
     "mid-range": "bun run src/mid-range-sellers-by-category.ts",
     "stalker": "bun run src/stalker.ts",
+    "search-offers": "bun run src/asin-offer-search.ts",
     "upc": "bun run src/upc-lookup.ts",
     "upc-file": "bun run src/upc-file-analysis.ts",
     "start": "bun run src/index.ts",