API updates:

- Mac class follows hashlib API: digest functions added and finalization no longer modifies state.
- Encryptor and Decryptor now raise RuntimeError if still used after final.

Documentation updated with the changes and  further examples.

Tests updated with the changes, new test module for error cases (test_raises).

Docstrings improved.

tests/test_mac.py

@@ -2,6 +2,7 @@ import json
 from pathlib import Path
 
 import pytest
+
 from pyaegis import aegis128l, aegis128x2, aegis128x4, aegis256, aegis256x2, aegis256x4
 
 from .util import random_split_bytes
@@ -81,10 +82,10 @@ def test_mac_class(vector):
     # Test 128-bit MAC if present
     if "tag128" in vector:
         expected_tag128 = bytes.fromhex(vector["tag128"])
-        mac_state = alg.Mac(key, nonce)
+        mac_state = alg.Mac(key, nonce, maclen=16)
         for chunk in random_split_bytes(data):
             mac_state.update(chunk)
-        computed_tag128 = mac_state.final(maclen=16)
+        computed_tag128 = mac_state.final()
         assert computed_tag128 == expected_tag128, (
             f"128-bit MAC mismatch for {vector['name']}"
         )
@@ -92,10 +93,10 @@ def test_mac_class(vector):
     # Test 256-bit MAC if present
     if "tag256" in vector:
         expected_tag256 = bytes.fromhex(vector["tag256"])
-        mac_state = alg.Mac(key, nonce)
+        mac_state = alg.Mac(key, nonce, maclen=32)
         for chunk in random_split_bytes(data):
             mac_state.update(chunk)
-        computed_tag256 = mac_state.final(maclen=32)
+        computed_tag256 = mac_state.final()
         assert computed_tag256 == expected_tag256, (
             f"256-bit MAC mismatch for {vector['name']}"
         )