C7 v2: add lease helpers and v2 page reset

core/box/tiny_hotheap_v2_box.h

@@ -0,0 +1,63 @@
+// tiny_hotheap_v2_box.h - TinyHotHeap v2 skeleton (Step1: types & stubs only)
+// 役割:
+//   - TinyHotHeap v2 の型と API を先行定義するが、現行経路には配線しない。
+//   - HAKMEM_TINY_HOTHEAP_V2 / HAKMEM_TINY_HOTHEAP_CLASSES で将来の A/B に備える。
+#pragma once
+
+#include <stdint.h>
+#include <string.h>
+
+#ifndef TINY_HOTHEAP_MAX_CLASSES
+#define TINY_HOTHEAP_MAX_CLASSES 8  // とりあえず全クラス分確保（後で mask で限定）
+#endif
+
+struct TinySlabMeta;
+struct SuperSlab;
+struct tiny_heap_page_t;  // from tiny_heap_box.h (v1 page型)
+
+typedef struct tiny_hotheap_page_v2 {
+    void*                   freelist;
+    uint16_t                used;
+    uint16_t                capacity;
+    uint16_t                slab_idx;
+    uint8_t                 _pad;
+    void*                   base;
+    struct TinySlabMeta*    meta;       // Superslab slab meta
+    struct SuperSlab*       ss;         // Owning Superslab (meta/ss_active の整合は v1 が保持)
+    struct tiny_heap_page_t* lease_page; // v1 側の page 構造体（freelist/used の正は常に lease_page）
+    struct tiny_hotheap_page_v2* next;
+} tiny_hotheap_page_v2;
+
+typedef struct tiny_hotheap_class_v2 {
+    tiny_hotheap_page_v2* current_page;
+    tiny_hotheap_page_v2* partial_pages;
+    tiny_hotheap_page_v2* full_pages;
+    uint16_t              stride;
+    uint16_t              _pad;
+    tiny_hotheap_page_v2  storage_page;  // C7 専用の 1 枚だけをまず保持
+} tiny_hotheap_class_v2;
+
+typedef struct tiny_hotheap_ctx_v2 {
+    tiny_hotheap_class_v2 cls[TINY_HOTHEAP_MAX_CLASSES];
+} tiny_hotheap_ctx_v2;
+
+// TLS state (定義は core/hakmem_tiny.c)
+extern __thread tiny_hotheap_ctx_v2* g_tiny_hotheap_ctx_v2;
+
+// API (Step1: まだ中身はダミー)
+tiny_hotheap_ctx_v2* tiny_hotheap_v2_tls_get(void);
+void* tiny_hotheap_v2_alloc(uint8_t class_idx);
+void tiny_hotheap_v2_free(uint8_t class_idx, void* p, void* meta);
+
+static inline void tiny_hotheap_v2_page_reset(tiny_hotheap_page_v2* page) {
+    if (!page) return;
+    page->freelist = NULL;
+    page->used = 0;
+    page->capacity = 0;
+    page->slab_idx = 0;
+    page->base = NULL;
+    page->meta = NULL;
+    page->ss = NULL;
+    page->lease_page = NULL;
+    page->next = NULL;
+}