Request coverage for a place

Increments the demand counter for a place so coverage expansion follows constituent demand, for agents told that place is unsupported. Call this when locus_coverage_check says a place is unsupported. Stores aggregate counts only; no requester identity. Direct flat-body route for this one free resource; no API key, payment, or catalog wrapper. Return only the cited bounded evidence described here; this route never produces a paid brief or full report.