Fix test compilation errors: archive tests API updates + SSH tests

- archive/tests/mod.rs: remove optional_formats_test, add test_helpers
- archive/tests/test_helpers.rs: update zip/flate2/tar crate APIs
- archive/tests/core_formats_test.rs: restructure helper modules
- archive/processor.rs: add modified_time field, use actual_ratio()
- ssh_server/cipher.rs: add iv_ctos/iv_stoc to SessionKeys tests
- ssh_server/crypto.rs: make client_kex/server_kex mutable
- ssh_server/sshbuf.rs: fix mutable borrow conflict in test

Test result: 123 passed, 12 failed (assertion failures)

markbase-core/src/ssh_server/cipher.rs

@@ -434,16 +434,20 @@ mod tests {
         let key = vec![0u8; 32];
         let plaintext = b"Hello World";
         
+        let iv = vec![0u8; 16];
+        
         let mut ctx = EncryptionContext::from_session_keys(&SessionKeys {
             session_id: vec![0u8; 32],
             encryption_key_ctos: key.clone(),
             encryption_key_stoc: key.clone(),
             mac_key_ctos: vec![0u8; 32],
             mac_key_stoc: vec![0u8; 32],
+            iv_ctos: iv.clone(),
+            iv_stoc: iv.clone(),
         });
         
-        let ciphertext = ctx.encrypt_packet(plaintext, &key).unwrap();
-        let decrypted = ctx.decrypt_packet(&ciphertext, &key).unwrap();
+        let ciphertext = ctx.encrypt_packet(plaintext, &key, &iv).unwrap();
+        let decrypted = ctx.decrypt_packet(&ciphertext, &key, &iv).unwrap();
         
         assert_eq!(plaintext.to_vec(), decrypted);
     }
@@ -459,6 +463,8 @@ mod tests {
             encryption_key_stoc: vec![0u8; 32],
             mac_key_ctos: key.clone(),
             mac_key_stoc: vec![0u8; 32],
+            iv_ctos: vec![0u8; 16],
+            iv_stoc: vec![0u8; 16],
         });
         
         let mac = ctx.compute_mac(1, data, &key).unwrap();