Priority-2: ENV Cache - Warm Path (FastCache/SuperSlab) getenv() 置換

変更内容:
- hakmem_env_cache.h: 2つの新ENV変数を追加
  (TINY_FAST_STATS, TINY_UNIFIED_CACHE)
- tiny_fastcache.c: 2箇所の getenv() を置換
  (TINY_PROFILE, TINY_FAST_STATS)
- tiny_fastcache.h: 1箇所の getenv() を置換
  (TINY_PROFILE in inline function)
- superslab_slab.c: 1箇所の getenv() を置換
  (TINY_SLL_DIAG)
- tiny_unified_cache.c: 1箇所の getenv() を置換
  (TINY_UNIFIED_CACHE)

効果: Warm path層からも syscall を排除 (ENV変数数: 28→30)

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

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

core/tiny_fastcache.h

@@ -6,8 +6,9 @@
 #include <stdint.h>
 #include <stddef.h>
 #include <string.h>
-#include <stdlib.h>  // For getenv()
-#include "box/tiny_next_ptr_box.h"  // Box API: Next pointer read/write
+#include <stdlib.h>
+#include "hakmem_env_cache.h"             // Priority-2: ENV cache (eliminate syscalls)
+#include "box/tiny_next_ptr_box.h"        // Box API: Next pointer read/write
 
 // ========== Configuration ==========
 
@@ -68,10 +69,10 @@ static inline uint64_t tiny_fast_rdtsc(void) { return 0; }
 extern int g_profile_enabled;
 static inline int tiny_fast_profile_enabled(void) {
 #if !HAKMEM_BUILD_RELEASE
+    // Priority-2: Use cached ENV (eliminate lazy-init inline overhead)
     extern int g_profile_enabled;
     if (__builtin_expect(g_profile_enabled == -1, 0)) {
-        const char* env = getenv("HAKMEM_TINY_PROFILE");
-        g_profile_enabled = (env && *env && *env != '0') ? 1 : 0;
+        g_profile_enabled = HAK_ENV_TINY_PROFILE();
     }
     return g_profile_enabled;
 #else