## Issue Addressed
NA
## Proposed Changes
Avoids reprocessing loops introduced in #4179. (Also somewhat related to #4192).
Breaks the re-queue loop by only re-queuing when an RPC block is received before the attestation creation deadline.
I've put `proposal_is_known` behind a closure to avoid interacting with the `observed_proposers` lock unnecessarily.
## Additional Info
NA
## Issue Addressed
Closes#4185
## Proposed Changes
- Set user agent to `Lighthouse/vX.Y.Z-<commit hash>` by default
- Allow tweaking user agent via `--builder-user-agent "agent"`
## Proposed Changes
Builds on #4028 to use the new payload bodies methods in the HTTP API as well.
## Caveats
The payloads by range method only works for the finalized chain, so it can't be used in the execution engine integration tests because we try to reconstruct unfinalized payloads there.
## Issue Addressed
NA
## Proposed Changes
Apply two changes to code introduced in #4179:
1. Remove the `ERRO` log for when we error on `proposer_has_been_observed()`. We were seeing a lot of this in our logs for finalized blocks and it's a bit noisy.
1. Use `false` rather than `true` for `proposal_already_known` when there is an error. If a block raises an error in `proposer_has_been_observed()` then the block must be invalid, so we should process (and reject) it now rather than queuing it.
For reference, here is one of the offending `ERRO` logs:
```
ERRO Failed to check observed proposers block_root: 0x5845…878e, source: rpc, error: FinalizedBlock { slot: Slot(5410983), finalized_slot: Slot(5411232) }
```
## Additional Info
NA
## Issue Addressed
NA
## Proposed Changes
Similar to #4181 but without the version bump and a more nuanced fix.
Patches the high CPU usage seen after the Capella fork which was caused by processing exits when there are skip slots.
## Additional Info
~~This is an imperfect solution that will cause us to drop some exits at the fork boundary. This is tracked at #4184.~~
