Implement Fan-In Fan-Out Pattern for NSFW Image Processing

Implement the Fan-In Fan-Out concurrency pattern for efficient processing of NSFW image detection. The process involves two distinct worker types:

-> Downloader Workers (Fan-Out):

Gather and download files.
After downloading, place the file references into a shared queue.

-> Scanner Workers (Fan-In):

Extract file references from the shared queue.
Run the NSFW scanner on each file.
Determine if the file is NSFW or safe.