Implement Python bindings for the libaegis 0.10.6 RAF API:
- Thin per-variant wrappers (raf_create/open/read/write/truncate/size/
sync/close, merkle_rebuild/verify/commitment) generated from a template
in tools/generate.py, with errno-mapped exceptions.
- aeg.raf: high-level file-like API (Raf, create/open/probe,
derive_master_key) with pluggable Storage backends (FileStorage,
BytesIOStorage) and Merkle tree integrity via a MerkleHasher protocol
(SHA256MerkleHasher default), adapted from pyaegis (MIT).
- aeg.random: CSPRNG facility. Random produces AEGIS keystream seeded
once from the OS, exposed per cipher module as cipher.random() and
usable as the RAF RNG (as_raf_rng) or standalone RandomSource.
- Tests: roundtrip/random-access/seek/truncate/Merkle coverage for all
six variants, pyaegis-style API checks, and a Merkle fuzz test.
- 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.