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.

include/se050_scp03.h

@@ -12,6 +12,7 @@
 
 /* Forward declarations */
 typedef struct se050_session_ctx se050_session_ctx_t;
+typedef struct se050_scp03_ctx se050_scp03_ctx_t;
 
 /* SCP03 key sizes */
 #define SCP03_KEY_SIZE  16