Fix WebView2 square glow artifact on transfer rings

[kmassoud05]

#64 - This fixes the square glow artifact seen behind active transfer rings in WebView2 on Windows.This fixes the square artifact seen behind active transfer rings in WebView2 on Windows.

Description

This PR removes the SVG glow filter from the transfer progress ring in styles.css. The filter was causing a square artifact to appear behind the circular ring in WebView2 on Windows, even though the ring itself was rendering correctly.

The change keeps the ring’s progress behavior and state styling intact while removing the problematic visual effect. This is a UI-only fix and does not change the downloader logic or introduce new dependencies.

Type of change

• [✅ ] Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would change existing behavior)
• Documentation update
• Refactor / code cleanup
• Other:

Checklist

• [✅ ] I have tested my changes locally
• If this affects shared logic (extraction, download engine), I also
  applied the equivalent change to moon_cli.py
• [✅ ] I have kept the single-file architecture (no package split)
• [✅ ] I have not added new dependencies without justification in the PR
  description

Screenshots / logs (if applicable)