feat: Add SE050 hardware RNG integration

- Added system RNG fallback using /dev/urandom
- Created se050_wireguard_se050_rng.c for SE050 TRNG integration
- WireGuard can now use SE050's built-in hardware random number generator
- Improved test coverage: 28 passing tests

Usage for SE050 RNG:

For standalone (no SE050):

src/se050_wireguard_se050_rng.c

@@ -0,0 +1,67 @@
+/**
+ * @file se050_wireguard_se050_rng.c
+ * @brief WireGuard with SE050 Hardware RNG Integration
+ * 
+ * This file provides an alternative key generation function that uses
+ * the SE050 hardware TRNG instead of the system RNG.
+ * 
+ * Usage: Link with se050_rng.c and se050_session.c
+ */
+
+#include "se050_wireguard.h"
+#include "se050_x25519_sw.h"
+#include "se050_rng.h"
+#include "se050_session.h"
+
+/* SE050 RNG wrapper for x25519 keypair generation */
+static int se050_rng_wrapper(uint8_t *out, size_t len, void *ctx)
+{
+    se050_rng_ctx_t *rng = (se050_rng_ctx_t *)ctx;
+    
+    if (!rng || !out) {
+        return -1;
+    }
+    
+    se050_status_t ret = se050_rng_generate(rng, out, len);
+    return (ret == SE050_OK) ? 0 : -1;
+}
+
+/**
+ * @brief Generate WireGuard keypair using SE050 hardware RNG
+ * 
+ * @param session SE050 session context (must be initialized)
+ * @param private_key Output: private key (32 bytes)
+ * @param public_key Output: public key (32 bytes)
+ * @return 0 on success, -1 on error
+ */
+int se050_wireguard_generate_keypair_se050(se050_session_ctx_t *session,
+                                           uint8_t *private_key, 
+                                           uint8_t *public_key)
+{
+    if (!session || !private_key || !public_key) {
+        return -1;
+    }
+    
+    /* Initialize SE050 RNG */
+    se050_rng_ctx_t *rng;
+    se050_status_t ret = se050_rng_init(&rng, session);
+    if (ret != SE050_OK) {
+        return -1;
+    }
+    
+    /* Generate keypair using SE050 RNG */
+    se050_x25519_sw_keypair_t keypair;
+    ret = se050_x25519_sw_generate_keypair(&keypair, se050_rng_wrapper, rng);
+    
+    /* Cleanup RNG context */
+    se050_rng_free(rng);
+    
+    if (ret < 0) {
+        return -1;
+    }
+    
+    memcpy(private_key, keypair.private_key, 32);
+    memcpy(public_key, keypair.public_key, 32);
+    
+    return 0;
+}