Refactor SP-API test script and improve type definitions

- Updated `sp-test.ts` to enhance argument parsing and error handling for sellability checks.
- Refactored `types.ts` to maintain consistent formatting and improve readability.
- Improved `writer.ts` for better result handling and CSV writing, ensuring clarity in output.
- Adjusted `tsconfig.json` formatting for consistency and readability.

.env.example

@@ -1,15 +1,15 @@
-KEEPA_API_KEY=your_keepa_api_key_here
-SP_API_CLIENT_ID=your_sp_api_client_id
-SP_API_CLIENT_SECRET=your_sp_api_client_secret
-SP_API_REFRESH_TOKEN=your_sp_api_refresh_token
-SP_API_REGION=na
-SP_API_MARKETPLACE_ID=ATVPDKIKX0DER
-SP_API_SELLER_ID=your_seller_id
-SP_API_USE_SANDBOX=false
-AWS_ACCESS_KEY_ID=your_aws_access_key_id
-AWS_SECRET_ACCESS_KEY=your_aws_secret_access_key
-# AWS_SESSION_TOKEN=optional_if_using_sts
-REDIS_URL=redis://localhost:6379
-LLM_URL=http://localhost:1234/v1
-LLM_MODEL=default
-CACHE_TTL=86400
+KEEPA_API_KEY=your_keepa_api_key_here
+SP_API_CLIENT_ID=your_sp_api_client_id
+SP_API_CLIENT_SECRET=your_sp_api_client_secret
+SP_API_REFRESH_TOKEN=your_sp_api_refresh_token
+SP_API_REGION=na
+SP_API_MARKETPLACE_ID=ATVPDKIKX0DER
+SP_API_SELLER_ID=your_seller_id
+SP_API_USE_SANDBOX=false
+AWS_ACCESS_KEY_ID=your_aws_access_key_id
+AWS_SECRET_ACCESS_KEY=your_aws_secret_access_key
+# AWS_SESSION_TOKEN=optional_if_using_sts
+REDIS_URL=redis://localhost:6379
+LLM_URL=http://localhost:1234/v1
+LLM_MODEL=default
+CACHE_TTL=86400