unify(pathfinder): Merge local variable optimizations in PathfindZoneManager::calculateZones() from Zero Hour

[Mauller]

This PR backports some optimisations from the Zero Hour version of PathfindZoneManager::calculateZones() to make the unification diff a little smaller and easier to comprehend.

This PR adds some local variables for PathfindCell and Zone values that are reused multiple times so the array they are contained within is not constantly accessed on the heap.

[greptile-apps]

Greptile Summary

Added local variable optimizations to PathfindZoneManager::calculateZones() by introducing reference variables (cell, r_thisLayer, r_thisCell, r_leftCell, r_topCell) that cache frequently-accessed array elements, reducing redundant heap accesses.

Key Changes:

• Introduced PathfindCell &cell to cache map[i][j] in the zone remapping loop
• Introduced PathfindLayer &r_thisLayer to cache layers[i] in the layer processing loop
• Introduced PathfindCell &r_thisCell, r_leftCell, and r_topCell in the hierarchical zone calculation loop
• Local references for neighbor cells (r_leftCell, r_topCell) are correctly created inside boundary-checked conditional blocks, preventing out-of-bounds access
• All neighbor references properly marked as const since they are read-only

Confidence Score: 5/5

• This PR is safe to merge with no risk
• This is a clean performance optimization that reduces heap accesses by caching array elements in local references. The refactoring preserves all original logic, properly handles boundary conditions with short-circuit evaluation, and uses const-correctness appropriately. Previous concerns about out-of-bounds access have been addressed by placing neighbor cell references inside boundary-checked blocks.
• No files require special attention

Important Files Changed

Filename	Overview
Generals/Code/GameEngine/Source/GameLogic/AI/AIPathfind.cpp	Added local variable references to reduce heap accesses in zone calculation loops; boundary checks properly protect against out-of-bounds access

_{Last reviewed commit: cc74ab2}

[greptile-apps]

_{2 files reviewed, 6 comments}

_{Edit Code Review Agent Settings | Greptile}

[Mauller]

Tweaked based on feedback, also ported that tweak to the Zero Hour version as well

[Mauller]

Just reverted that change as it could have been dangerous in the end.