Clean module at src/performance/ with all verified permanent
optimizations and zero profiling overhead. No rdtsc, no A/B testing,
no probe counters, no dumpStats.
Hooks: transformMatrix4x4 bone SSE, RenderParticleSprites SSE,
GetOrCreateCharacterGlyph cache, OnWorldUpdate cache reset,
teardown guard.
SSE compilation units (bone_sse, particle_sse, clip_sse, silicon_sse)
moved to src/performance/ as canonical location.
Build: zig build -Dperformance=true -Dsilicon=true
(transform44 module remains available for profiling/development)
