feat(engine): batch multiproof messages

[0xSooki]

trafficstars

fixes #19168

Batching additions:

• Added batching for PrefetchProofs messages
• Added batching for StateUpdate messages

Testing enhancements:

• Added test_prefetch_proofs_batching to verify that multiple PrefetchProofs messages are correctly batched and processed as a single unit.
• Added test_state_update_batching to ensure that multiple StateUpdate messages are merged and handled together as intended.