Fix Gloas clearance

[ahshum]

Summary

• check parent envelope before adding block to clearance state.
  • same check in block_processor in order to mark envelope as missing with new VerifierError
• updateState() when adding envelope to clearance state.
  • check slot and root of envelope with state instead of block
• Modify addPayload() to handle MissingParent error.
• FcU correctly

[github-actions]

Unit Test Results

       12 files  ±0    2 488 suites  ±0   48m 45s ⏱️ - 10m 38s
12 978 tests ±0  12 431 ✔️ ±0  547 💤 ±0  0 ❌ ±0 
65 612 runs  ±0  64 902 ✔️ ±0  710 💤 ±0  0 ❌ ±0 

Results for commit ca11695. ± Comparison against base commit b10e378.

♻️ This comment has been updated with latest results.

[tersec]

Merge conflict with beacon_chain/gossip_processing/block_processor.nim.

[ahshum]

Taking out e79a45d as it would be replaced by a new VerifierError and handler. And it seems it breaks block_sims.

[tersec]

2026-03-24T15:55:17.8310404Z Block processor [Preset: mainnet] ........F.F. (14.1s)
2026-03-24T15:55:17.8311524Z =======================================================================
2026-03-24T15:55:17.8321162Z   /github-runner/github-runner-node-02/workspace/nimbus-eth2/nimbus-eth2/build/all_tests 'Block processor [Preset: mainnet]::Gloas block pops pre-arrived envelope from quarantine [Preset: mainnet]'
2026-03-24T15:55:17.8322783Z -----------------------------------------------------------------------
2026-03-24T15:55:17.8324360Z     /github-runner/github-runner-node-02/workspace/nimbus-eth2/nimbus-eth2/tests/test_block_processor.nim(470, 32): Check failed: engineBlock.blck.root notin envelopeQuarantine[].getMissing()
2026-03-24T15:55:17.8325666Z 
2026-03-24T15:55:17.8326433Z   [FAILED ] (  1.19s) Gloas block pops pre-arrived envelope from quarantine [Preset: mainnet]
2026-03-24T15:55:17.8327083Z 
2026-03-24T15:55:17.8327286Z ================================================================
2026-03-24T15:55:17.8328784Z   /github-runner/github-runner-node-02/workspace/nimbus-eth2/nimbus-eth2/build/all_tests 'Block processor [Preset: mainnet]::Gloas reverse order blocks with missing parent [Preset: mainnet]'
2026-03-24T15:55:17.8330811Z ----------------------------------------------------------------
2026-03-24T15:55:17.8332133Z     /github-runner/github-runner-node-02/workspace/nimbus-eth2/nimbus-eth2/tests/test_block_processor.nim(544, 31): Check failed: dag.containsForkBlock(b2.root)
2026-03-24T15:55:17.8333225Z 
2026-03-24T15:55:17.8333773Z   [FAILED ] (  1.21s) Gloas reverse order blocks with missing parent [Preset: mainnet]
2026-03-24T15:55:17.8334377Z