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_session_internal.h

@@ -10,6 +10,7 @@
 #ifndef SE050_SESSION_INTERNAL_H
 #define SE050_SESSION_INTERNAL_H
 
+#include "se050_i2c_hal.h"
 #include "se050_wireguard.h"
 #include <stdint.h>