feat: add throughput-aware progress reporting for hashing

[KGFCH2]

@Rakshat28

Addresses #46.

Summary

This PR introduces a richer and more informative progress reporting system for the hashing phase of bdstorage, improving visibility and usability during long-running scans.

Key Changes

Byte-Level Progress Tracking

• Reworked hashing progress measurement from:
  • "files completed"
  • to "bytes processed"
• Produces a significantly smoother and more accurate progress bar, especially for datasets containing a mix of very small and extremely large files.

Performance Metrics

• Added real-time throughput and ETA reporting.
• Users can now monitor:
  • Current processing speed
  • Estimated completion time
  • Overall scan progress

Terminal-Aware Output

• Implemented automatic detection for non-interactive output environments.
• ANSI escape sequences are now suppressed when output is:
  • Redirected
  • Piped
  • Logged to files
• Ensures clean, script-friendly terminal output.

Quiet Mode

• Added a -q flag for silent execution.
• Useful for automation, scripting, and minimal-output workflows.

Result

These improvements make bdstorage feel substantially more responsive and polished when processing large-scale datasets, including multi-terabyte archives and network-mounted storage collections.