Function decode_payload 

fn decode_payload(id: i64, raw: &[u8]) -> Value

Decode a stored msgpack payload. A decode failure indicates persisted data corruption (schema mismatch, truncation, etc.), so we surface it loudly (log::error) so operators see it, but return null for the payload instead of failing the whole list — a single poisoned row shouldn’t take down the bell for the wallet’s entire history. The fail-loud log + null payload is the compromise between AGENTS.md’s fail-fast-on-invariant rule and read-path availability.