Generate a shareable 1080x1350 JPEG personal colour analysis card.

DELIBERATELY DISABLED (fix/llm-route-auth follow-up).

Authentication runs first and is unchanged: invalid or absent credentials still terminate here with a 401, before anything else. Once authenticated, this feature is simply not available -- it does NOT proceed to Vision or any other paid model call. This endpoint used to look up a route registered at the path "/personal-colour-analysis", which does not exist (the real route is "/image/personal"), so it always failed with a 500 before reaching the model. Wiring it up to the real analysis core would make it newly functional -- more scope than intended here -- so it stays off, deliberately and visibly, until that is its own decision.