Add retry mechanism for payload envelope DB persistence #9072

Context

In persistPayloadEnvelopeInput(), a DB write failure causes the in-memory PayloadEnvelopeInput to be pruned via .finally(), losing data from both DB and memory with no recovery path. This is the same pattern as persistBlockInput().

Current behavior

await writePayloadEnvelopeInputToDb.call(this, payloadInput)
  .catch((e) => {
    this.logger.error("Error persisting payload envelope in hot db", {...}, e);
  })
  .finally(() => {
    this.seenPayloadEnvelopeInput.prune(payloadInput.blockRootHex);
    // ...
  });

On a transient DB error (disk full, I/O timeout), .catch() logs the error but .finally() still prunes the in-memory data. The envelope is now gone from both DB and memory — irrecoverable.

Proposed fix

1. Only prune on success (move prune from .finally() to .then())
2. Add a retry mechanism for transient failures (exponential backoff, bounded retries)
3. Apply the same fix to persistBlockInput() which has the identical pattern

References

• PR feat: add gloas execution payload envelope import pipeline #8962 — writePayloadEnvelopeInputToDb.ts (review thread)
• Same pattern exists in persistBlockInput() (noted by @twoeths)

/cc @nflaig @twoeths