oklchToRgb read the colour back from the browser's CSS engine and expected
rgb(...). Current Chromium (the kiosk's 153) resolves an oklch colour to
oklch(...), so the match failed and every swatch fell back to [255, 255, 255]:
tapping a colour set the light to white. It now does the OKLab maths itself.
Also log a Home Assistant call that fails in the proxy: httpx only logs a
request once it has a response, so a call that timed out left no trace.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>