When Besu is behind the CL head (e.g., during initial sync or after restart),
desync-tolerance=0 prevents maru from sending any fork choice updates to Besu.
This causes Besu to remain stuck at its current block.
Increasing desync-tolerance to 100000 allows maru to continue sending blocks
even when Besu is significantly behind, enabling it to catch up.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>