Phase 83-1 + Allocator Comparison: Switch dispatch fixed (NO-GO +0.32%), PROFILE correction, SCORECARD update

Key changes:
- Phase 83-1: Switch dispatch fixed mode (tiny_inline_slots_switch_dispatch_fixed_box) - NO-GO (marginal +0.32%, branch reduction negligible)
  Reason: lazy-init pattern already optimal, Phase 78-1 pattern shows diminishing returns

- Allocator comparison baseline update (10-run SSOT, WS=400, ITERS=20M):
  tcmalloc: 115.26M (92.33% of mimalloc)
  jemalloc: 97.39M (77.96% of mimalloc)
  system: 85.20M (68.24% of mimalloc)
  mimalloc: 124.82M (baseline)

- hakmem PROFILE correction: scripts/run_mixed_10_cleanenv.sh + run_allocator_quick_matrix.sh
  PROFILE explicitly set to MIXED_TINYV3_C7_SAFE for hakmem measurements
  Result: baseline stabilized to 55.53M (44.46% of mimalloc)
  Previous unstable measurement (35.57M) was due to profile leak

- Documentation:
  * PERFORMANCE_TARGETS_SCORECARD.md: Reference allocators + M1/M2 milestone status
  * PHASE83_1_SWITCH_DISPATCH_FIXED_RESULTS.md: Phase 83-1 analysis (NO-GO)
  * ALLOCATOR_COMPARISON_QUICK_RUNBOOK.md: Quick comparison procedure
  * ALLOCATOR_COMPARISON_SSOT.md: Detailed SSOT methodology

- M2 milestone status: 44.46% (target 55%, gap -10.54pp) - structural improvements needed

🤖 Generated with Claude Code
Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

core/tiny_c2_local_cache.c

@@ -0,0 +1,17 @@
+// tiny_c2_local_cache.c - Phase 79-1: C2 Local Cache TLS Variable Definition
+//
+// Goal: Define TLS variable for C2 local cache ring buffer
+// Scope: C2 class only
+// Design: Zero-initialized __thread variable
+
+#include "box/tiny_c2_local_cache_tls_box.h"
+
+// ============================================================================
+// C2 Local Cache: TLS Variable Definition
+// ============================================================================
+
+// TLS ring buffer for C2 local cache
+// Automatically zero-initialized for each thread
+// Name: g_tiny_c2_local_cache
+// Size: 512B per thread (64 slots × 8 bytes + 64 bytes padding)
+__thread TinyC2LocalCache g_tiny_c2_local_cache = {0};