Critical fix for grid auto-adjustment:
- Recalculate grid bounds (UpperPrice, LowerPrice, GridSpacing) centered
on current price before reinitializing grid levels
- Preserve filled positions during adjustment by saving and restoring
them to the closest new level after reinitialization
- Hold mutex lock for the entire adjustment operation to ensure atomicity
- Add locked variants of calculateDefaultBounds, calculateATRBounds, and
initializeGridLevels to use during adjustment
Without this fix, autoAdjustGrid was using old boundaries when creating
new grid levels, defeating the purpose of auto-adjustment when price
moved significantly.
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