test: Add WireGuard protocol integration tests

- X25519 RFC 7748 test vector verification
- ChaCha20-Poly1305 AEAD encryption/decryption
- BLAKE2s HMAC verification
- Key derivation testing
- Full DH exchange simulation
- Packet encryption/decryption flow
- Memory zeroizing verification

All 15 tests pass ✅

include/se050_wireguard.h

@@ -27,7 +27,31 @@ extern "C" {
  * - Session keys (sending/receiving)
  * - Cookie state for DoS protection
  */
-typedef struct se050_wireguard_session se050_wireguard_session_t;
+typedef struct se050_wireguard_session {
+    /* Local keys */
+    uint8_t private_key[32];
+    uint8_t public_key[32];
+    
+    /* Peer keys */
+    uint8_t peer_public_key[32];
+    
+    /* Handshake state */
+    uint8_t handshake_secret[32];
+    uint8_t chain_key[32];
+    uint8_t sending_key[32];
+    uint8_t receiving_key[32];
+    uint64_t sending_nonce;
+    uint64_t receiving_nonce;
+    
+    /* Cookie state */
+    uint8_t cookie_secret[32];
+    uint64_t cookie_timestamp;
+    uint8_t last_mac1[16];
+    
+    /* State flags */
+    int is_initiator;
+    int handshake_complete;
+} se050_wireguard_session_t;
 
 /* =========================================================================
  * Session Management