Find a transaction on every indexed network at once

One hash, no network: every indexed network whose transaction-id form the hash fits is searched (hex — the EVM networks and Tron; base58 — Solana) for stablecoin transfers and issuer acts, the same reads as /v1/transfers?tx= and /v1/freezes?tx=. found is true on a hit (chain_id, transfers, freeze describe it), false when every searched network answered without one, and null when none found it and at least one network did not answer (chains[].status: unknown) — retry, it is not a negative. A negative covers each network's hot window as of its chains[].sync (read freshness_seconds); rows older than hot_window_start are offloaded and not searched. Unknown parameters, chain included, are 400 unknown_param. Incomplete answers are no-store; complete ones live 15 s.