Warm Reaction Service

Start booting the GPU container. Generates nothing, costs no clip.

The app calls this when a child is shown the "make X your best friend?" confirmation: if they say yes a second later the crowning's twelve clips would otherwise open with a 30-90 s cold start, and this overlaps that boot with the time they spend deciding.

NO ENTITLEMENT GATE, on purpose — nothing is generated and nothing is spent on the child's behalf; the crowning itself is where the stars and the entitlement are checked. Answers 202 immediately and never reports a failure: a child looking at a confirmation must not be shown an error from an optimisation they never asked for.

Declared before /reactions/{reaction_id} so "warm" is not read as an id.