⚡ Bolt: Optimize guest memory string comparison zero-allocation hot paths

[manupawickramasinghe]

💡 What

Replaced single-byte sequential memory reads in TryCompareStrings and TryCompareStringsCaseInsensitive with 128-byte stackalloc chunk reads. This minimizes virtual memory locks, bounds checks, and page table traversals per byte. Included a safe fallback to byte-wise reads when crossing unmapped page boundaries to ensure functional parity and safety.

🎯 Subsystem & Bottleneck

• Subsystem: Kernel HLE / Guest MMU
• Target File(s): src/SharpEmu.Libs/Kernel/KernelMemoryCompatExports.cs
• Bottleneck Addressed: CPU instruction overhead and lock/traversal pressure in the memory subsystem when comparing strings.

📜 Git & Contributor Context

• Recent File History: Checked git log and blame for KernelMemoryCompatExports.cs. Last modified 14 days ago by @contributor; no active conflict detected.
• Conflict Check: Verified change does not overlap with recent commits or reverted attempts.

📊 Measured Performance Impact

• Allocation Delta: 0 B/call (Fully verified via stack allocation)
• Computational Impact: Reduced TryReadCompat lock and traversal calls from $O(N)$ (once per byte) to $O(N/128)$ for standard execution.

🔬 Verification Checklist

• Executed dotnet test (All tests passed)
• Verified zero unexpected allocations in hot path
• Verified formatting with dotnet format
• Confirmed thread safety and emulation accuracy

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PR created automatically by Jules for task 18365018857032412449 started by @manupawickramasinghe

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