[codex] Fix WebGL2 runtime for Selenium Chrome sessions

[chenchenchenchencj]

Summary

Fixes #12.

This PR keeps the DeskClaw/WebGL2 fix scoped to Browser Pilot's Selenium Chrome runtime and existing fingerprint health UI:

• enable WebGL2 alongside WebGL in the Chrome launch path
• prefer ANGLE + SwiftShader for Chromium on ARM where native/egl paths can fail
• install GLES/Mesa runtime libraries and add a Chromium GLES fallback symlink when needed
• record WebGL2 context availability in runtime health checks
• surface WebGL2 unavailable/available state in the noVNC fingerprint status display

Root cause

DeskClaw's workspace canvas uses Three.js and requires WebGL2. On ARM Chromium sessions, the previous default software GL path could leave WebGL/WebGL2 context creation unavailable, so the workspace rendered as a blank/dark canvas even though the session itself was connected.

Validation

• python3 -m py_compile services/selenium-chrome/cdp-fingerprint-agent.py
• bash -n services/selenium-chrome/start-browser.sh
• npm run build from frontend/
• Manual Browser Pilot session test: DeskClaw workspace canvas renders after rebuilding the Selenium Chrome image with the updated WebGL runtime path.