v8.0.0

Quiet Avalonia log sink to Fatal-only (suppress WSL/Linux noise)

GLX blacklist and DBus connection errors are non-fatal on WSL/Linux
but printed to stderr at Error level, alarming users. Raise sink
threshold to Fatal so only actual crashes produce console output.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>