Comprehensive legacy cleanup and architecture consolidation

Summary of Changes:

MOVED TO ARCHIVE:
- core/hakmem_tiny_legacy_slow_box.inc → archive/
  * Slow path legacy code preserved for reference
  * Superseded by Gatekeeper Box architecture

- core/superslab_allocate.c → archive/superslab_allocate_legacy.c
  * Legacy SuperSlab allocation implementation
  * Functionality integrated into new Box system

- core/superslab_head.c → archive/superslab_head_legacy.c
  * Legacy slab head management
  * Refactored through Box architecture

REMOVED DEAD CODE:
- Eliminated unused allocation policy variants from ss_allocation_box.c
  * Reduced from 127+ lines of conditional logic to focused implementation
  * Removed: old policy branches, unused allocation strategies
  * Kept: current Box-based allocation path

ADDED NEW INFRASTRUCTURE:
- core/superslab_head_stub.c (41 lines)
  * Minimal stub for backward compatibility
  * Delegates to new architecture

- Enhanced core/superslab_cache.c (75 lines added)
  * Added missing API functions for cache management
  * Proper interface for SuperSlab cache integration

REFACTORED CORE SYSTEMS:
- core/hakmem_super_registry.c
  * Moved registration logic from scattered locations
  * Centralized SuperSlab registry management

- core/hakmem_tiny.c
  * Removed 27 lines of redundant initialization
  * Simplified through Box architecture

- core/hakmem_tiny_alloc.inc
  * Streamlined allocation path to use Gatekeeper
  * Removed legacy decision logic

- core/box/ss_allocation_box.c/h
  * Dramatically simplified allocation policy
  * Removed conditional branches for unused strategies
  * Focused on current Box-based approach

BUILD SYSTEM:
- Updated Makefile for archive structure
- Removed obsolete object file references
- Maintained build compatibility

SAFETY & TESTING:
- All deletions verified: no broken references
- Build verification: RELEASE=0 and RELEASE=1 pass
- Smoke tests: 100% pass rate
- Functional verification: allocation/free intact

Architecture Consolidation:
Before: Multiple overlapping allocation paths with legacy code branches
After:  Single unified path through Gatekeeper Boxes with clear architecture

Benefits:
- Reduced code size and complexity
- Improved maintainability
- Single source of truth for allocation logic
- Better diagnostic/observability hooks
- Foundation for future optimizations

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

core/hakmem_tiny.c

@@ -206,9 +206,11 @@ static inline int fastcache_push(int class_idx, hak_base_ptr_t ptr);
 
 
 // ============================================================================ 
-// Legacy Slow Allocation Path - EXTRACTED to hakmem_tiny_legacy_slow_box.inc
+// Legacy Slow Allocation Path - ARCHIVED
 // ============================================================================ 
-#include "hakmem_tiny_legacy_slow_box.inc"
+// Note: tiny_slow_alloc_fast() and related legacy slow path implementation
+// have been moved to archive/hakmem_tiny_legacy_slow_box.inc and are no
+// longer compiled. The current slow path uses Box化された hak_tiny_alloc_slow().
 
 
 // ============================================================================ 
@@ -493,18 +495,9 @@ static inline void* hak_tiny_alloc_superslab_try_fast(int class_idx) {
 #include "hakmem_tiny_smallmag.inc.h"
 
 // ============================================================================ 
-// Phase 6 Fast Path Options (mutually exclusive)
+// Phase 6 Fast Path Option (Metadata Header)
 // ============================================================================ 
-// Choose ONE of the following Phase 6 optimizations:
-//
-// Phase 6-1.5: Alignment Guessing (LEGACY - committed 2025-11-02)
-//   - Enable: -DHAKMEM_TINY_PHASE6_ULTRA_SIMPLE=1
-//   - Speed: 235 M ops/sec
-//   - Memory: 0% overhead
-//   - Method: Guess size class from pointer alignment (__builtin_ctzl)
-//   - Risk: Alignment assumptions may break with future changes
-//
-// Phase 6-1.6: Metadata Header (NEW - recommended for production)
+// Phase 6-1.6: Metadata Header (recommended)
 //   - Enable: -DHAKMEM_TINY_PHASE6_METADATA=1
 //   - Speed: 450-480 M ops/sec (expected, Phase 6-1 level)
 //   - Memory: ~6-12% overhead (8 bytes/allocation)
@@ -514,14 +507,6 @@ static inline void* hak_tiny_alloc_superslab_try_fast(int class_idx) {
 // ============================================================================ 
 
 // Forward declarations for Phase 6 alloc/free functions
-#ifdef HAKMEM_TINY_PHASE6_ULTRA_SIMPLE
-    void* hak_tiny_alloc_ultra_simple(size_t size);
-    void hak_tiny_free_ultra_simple(void* ptr);
-#endif
-
-#if defined(HAKMEM_TINY_PHASE6_METADATA) && defined(HAKMEM_TINY_PHASE6_ULTRA_SIMPLE)
-    #error "Cannot enable both PHASE6_METADATA and PHASE6_ULTRA_SIMPLE"
-#endif
 
 
 // ============================================================================