Major release. Highlights:
- Codec: vendored VaptVupt codec moves to canonical 2.60.4 security
release. Fixes a high-severity OOB heap write in the AVX2 decode fast
path (reachable on a valid stream sized to exactly content_size, both
tail variants). Brings CBMC-formally-verified BCJ filters with
automatic ELF/PE/Mach-O detection. Compressed output stays
byte-identical (ratio gate Δ 0.00%); wire format unchanged at v1.6.
- New --pq-box sealed-box recipient mode (vendored libpqvaptvupt 0.6.0):
ML-KEM-768 + X25519 combined via HKDF-SHA256 with domain separation,
AES-256-CTR + HMAC-SHA256 EtM. Legacy --pq and --pq-sdk stay readable.
- F-16: discloses and fixes a pre-existing data-loss defect in the
<= 3.8.0 in-tree BCJ encoder. Full back-compat matrix decodes
byte-exact under 4.0.0; every readable pre-4.0 archive remains readable.
Repository hygiene:
- Sync full 4.0.0 source tree (codec, crypto, SDK, GUI, packaging, tests).
- Remove internal scratch files (PROMPT.md, FORMAL_AUDIT_PROMPT.md)
and superseded version-specific docs (INTEGRATION_PROTOCOL_2.60.4.md,
docs/FINDINGS-2.x.md) and a stray test binary.
- Refresh README download/install section to real 4.0.0 release assets;
bump version badge to 4.0.0.
- Add .gitignore for build outputs (keeps vendored prebuilt libraries).
