fix: init wifi but skip autoconnect — iw scan causes 65ms frame drops
WiFi thread starts but doesn't scan until user requests it.
system("iw scan") triggers kernel radio scanning that blocks DRM
page flips for 65ms+ (4 missed vblanks). User can manually trigger
WiFi from the prompt when needed.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>