Covers the bridge doorway: a valid question is recorded and timestamped by the daemon (never the caller), missing or wrong secrets and malformed, oversized, or off-shape payloads are refused with nothing recorded, no cross-origin access is offered, queued answers are served and their delivery acknowledgements accepted, and everything answers "not found" when the bridge is off.

## Before writing SPEC.md files

Read https://raw.githubusercontent.com/brillout/sdd/refs/heads/main/sdd.md
