Remove dynamic memory allocation (malloc/calloc/free)

- Add static memory pool implementation (se050_mem_pool.c/h)
- Replace all malloc/calloc with pool allocations
- Replace all free with pool deallocations
- Remove strdup usage (use fixed-size buffer instead)
- Update I2C HAL to use fixed-size dev_path array
- All 24 tests pass with static memory only

Suitable for embedded environments (u-boot, ESP32) without heap.

src/se050_scp03.c

@@ -13,11 +13,11 @@
 #include "se050_i2c_hal.h"
 #include "se050_session_internal.h"
 #include "se050_scp03.h"
+#include "se050_mem_pool.h"
 #include "se050_wireguard.h"
 #include "se050_crypto_utils.h"
 #include "se050_mem_protect.h"
 #include <stdio.h>
-#include <stdlib.h>
 #include <string.h>
 
 /* SCP03 constants */
@@ -289,26 +289,17 @@ static se050_status_t scp03_derive_session_keys(se050_scp03_ctx_t *ctx)
 se050_status_t se050_scp03_init(se050_scp03_ctx_t **ctx, se050_session_ctx_t *session)
 {
     se050_scp03_ctx_t *scp03;
-    size_t ctx_size;
     
     if (!ctx || !session) {
         return SE050_ERR_INVALID_ARG;
     }
     
-    /* Allocate SCP03 context */
-    scp03 = (se050_scp03_ctx_t *)calloc(1, sizeof(*scp03));
+    /* Allocate SCP03 context from static pool */
+    scp03 = se050_scp03_alloc_pool();
     if (!scp03) {
         return SE050_ERR_FAIL;
     }
     
-    ctx_size = sizeof(*scp03);
-    
-    /* Apply memory protection (Linux only) */
-    if (protect_sensitive_memory(scp03, ctx_size) != SE050_OK) {
-        free(scp03);
-        return SE050_ERR_FAIL;
-    }
-    
     scp03->session = session;
     scp03->cmd_counter = 0;
     scp03->rsp_counter = 0;
@@ -340,11 +331,8 @@ void se050_scp03_free(se050_scp03_ctx_t *ctx)
         memzero_explicit(ctx->rsp_icv, sizeof(ctx->rsp_icv));
     }
     
-    /* Release memory protection before freeing */
-    release_memory_protection(ctx, sizeof(*ctx));
-    
-    /* Free SCP03 context */
-    free(ctx);
+    /* Free SCP03 context to static pool */
+    se050_scp03_free_pool(ctx);
 }
 
 se050_status_t se050_scp03_set_keys(se050_scp03_ctx_t *ctx,