feat: enhance configuration and rate limiting

- Added new configuration options: trustProxy, uploadConcurrency, batchMaxItems, batchMaxSizeBytes, and maxRequestBodyBytes to AppConfig.
- Implemented utility functions for parsing environment variables and masking sensitive data.
- Updated rate limiting logic to use configurable window size and maximum requests per window.
- Introduced a middleware for rate limiting on specific routes.
- Refactored file handling routes to support streaming downloads instead of redirects.
- Improved error handling and response formatting in file routes.
- Added support for oversized request rejection based on Content-Length header.
- Updated Swagger documentation to reflect changes in API behavior and responses.
- Enhanced tests to cover new features and ensure proper functionality.

src/utils/uploadBatcher.ts

@@ -34,8 +34,6 @@ type PendingUpload = BatchUploadItem & {
 };
 
 const BATCH_WINDOW_MS = 2000;
-const MAX_BATCH_ITEMS = 100;
-const MAX_BATCH_SIZE_BYTES = 2 * 1024 * 1024 * 1024;
 
 let pendingUploads: PendingUpload[] = [];
 let flushTimer: ReturnType<typeof setTimeout> | null = null;
@@ -142,7 +140,7 @@ export const enqueuePreparedUpload = (item: BatchUploadItem): Promise<UploadedFi
       }, BATCH_WINDOW_MS);
     }
 
-    if (pendingUploads.length >= MAX_BATCH_ITEMS || getPendingSize() >= MAX_BATCH_SIZE_BYTES) {
+    if (pendingUploads.length >= config.batchMaxItems || getPendingSize() >= config.batchMaxSizeBytes) {
       void flushUploads();
     }
   });