patch webRTC IP leaks + add disable WebGL option

[ethcipher]

Description

This PR adds two new config options to patch the WebRTC IP leaks:

• disable_webRTC (default: True)
  Stops WebRTC from leaking your real IP address when using a proxy.
  Behind the scenes, this sets:
• --webrtc-ip-handling-policy=disable_non_proxied_udp
• --force-webrtc-ip-handling-policy

Tested against browserleaks.com/webrtc no leaks after the patch

1 - this before the patch or now when disable_webRTC=False

2 - this after the patch and when disable_webRTC=True

• disable_webGL (default: False)
  Turns off WebGL (--disable-webgl, --disable-webgl2).
  This helps reduce fingerprinting since WebGL exposes GPU details. The Tor Browser disables WebGL for exactly this reason; the option is False. By default, you can enable it as shown in the example usage below.

Example usage

import zendriver as zd

config = zd.Config(
  disable_webRTC=True, # True by default
  disable_webGL=True   # False by default
)

Pre-merge Checklist

• I have described my change in the section above.
• I have ran the ./scripts/format.sh and ./scripts/lint.sh scripts. My code is properly formatted and has no linting errors.
• I have ran uv run pytest and ensured all tests pass.
• I have added my change to CHANGELOG.md under the [Unreleased] section.

[stephanlensky]

Hey @ethcipher, thanks for the contribution! I'm traveling right now and don't have a computer with me, but my initial thought is this looks great. I'll do a final review so we can get this merged when I return in a few weeks.