Optimize block iteration to prevent memory leaks

[LetMePractice]

Type of change

• Bug fix
• New feature

Description

Reworked block iteration to stop allocating new BlockPos objects inside hot loops.

The old implementation was creating a new BlockPos per iteration. Under heavy scripting this adds up to millions of allocations over time and eventually causes GC pressure and long-session instability.

Changes

• PlayerUtils.boxIterator() now uses BlockPos.Mutable
• runOnNearestBlock() / getNearestBlock() switched from cubic scan to spiral search and reuse a mutable position
• EntityUtils.runOnNearestBlock() updated the same way
• Raytracer.trace() reuses a single BlockPos.Mutable
• ConditionalBlockInFov rewritten to use a 3x3 raycast grid instead of block iteration

Impact

• Significantly lower allocation rate in hot paths
• Faster early exits with spiral search
• Removes sustained allocation pressure from block iteration

Related issues

Fixes long-session black screen when block_in_range / block_in_fov are used heavily in scripts.

Checklist:

• My code follows the style guidelines of ItziSpyder(ImproperIssues).
• I have added comments to my code in more complex areas.
• I have tested the code in both development and production environments.
• I have joined the ClickCrystals Discord.