Deterministic imagery plan for one event

Costs 4 token(s) per request (it deliberately issues two catalog searches). The SERVER decides which collections to search for the stated goal — sentinel-1-grd (SAR: all-weather, survives cloud and night) and sentinel-2-l2a (optical) exactly once each — against the event's own footprint and a pre/post window around its date, so the all-weather look can never be silently skipped and the same search is never repeated. Per search it reports why it was made, scenes returned, how many actually COVER the event and are usable (cloud-obscured optical does not count), the SAR pair status and whether a pre/post bracket exists, plus screening / detection / identification capability — a VHR recommendation never invalidates what the free catalog already showed. The vhr_recommendation.assessed flag says whether the VHR question was DECIDED at all: when the subject has no recorded ground-sampling requirement it comes back false, and recommended:false then means "not determined", NOT "not needed". An event with no resolvable footprint is refused rather than planned against a guess.