Rename module to pyaegis, implement build with zig.

examples/aegis256x4_demo.py

@@ -10,7 +10,7 @@ Covers:
 
 import time
 
-from aegis import aegis256x4 as a
+from pyaegis import aegis256x4 as a
 
 
 def hx(b, limit: int | None = None) -> str:

examples/benchmark.py

@@ -12,7 +12,7 @@ Output format and throughput units mirror the Zig benchmark (Mb/s).
 import os
 import time
 
-from aegis import aegis128l, aegis128x2, aegis128x4, aegis256, aegis256x2, aegis256x4
+from pyaegis import aegis128l, aegis128x2, aegis128x4, aegis256, aegis256x2, aegis256x4
 
 MSG_LEN = 16384000  # 16 MiB
 ITERATIONS = 100