release: v0.4.0

[N283T]

v0.4.0 — 2026-04-26

Changed

• More accurate error reporting: `XtcError` and `TrrError` gained `AccessDenied`, `IsDir`, `NoSpaceLeft`, and `IoError` variants. `XtcError` also gained `InvalidHeader`. (#25, #26, #27)
• Readers now reject directories at open time via `allow_directory = false`. (#25)
• Writer append paths preserve `InvalidMagic` / `InvalidHeader` instead of collapsing to `ReadError`. (#26)
• benchmark logs non-FileNotFound failures instead of silent skip. (#28)

Added

• macOS in CI matrix and cross-format tests run on every push (#29, ci: add macos-latest to CI matrix #31)
• `zig build converter-smoke` end-to-end smoke test for the converter binary (#30, test: add converter binary smoke test #33)
• IsDir tests for both readers and writers

Compatibility

New error variants are additive, but exhaustive switches will need new arms — minor bump.

Test plan

• All test steps pass locally on macOS (test 34, validate 36, cross-format 37)
• CI green on Linux + macOS