Resolves the 4 P3 items in docs/rewrite/notes/review-rv13-codex.md
(final-Z16.md):
- async-backend now takes effect like Ghostty: ghostty_os::xev ports
libxev's backend detection (io_uring, then epoll); global init detects
and logs it, the GTK startup applies the config with Zig's messages,
and +version reports the real backend. The termio IO loop runs on a
new reactor with epoll, io_uring (io-uring crate) and poll(2) (kept
for macOS, where libxev uses kqueue). The 21 exec integration tests
run under every backend; io_uring was exercised here.
- auto-update-channel defaults to the build's release channel.
- Windows error names: sharing violation -> AccessDenied, plus
ERROR_FILE_EXISTS -> PathAlreadyExists and virus errors ->
AntivirusInterference, mirroring std.os.windows.OpenFile's NTSTATUS
mapping in Zig 0.15.2 (verified against its source by the
orchestrator).
- Exact ports of std.fs.path.basenameWindows/basenamePosix for theme
name validation (drive, UNC and device roots).
Test Plan:
- cargo test --workspace --no-fail-fast (3555 passed, exit 0)
- just check-macos (both), just check-windows, just check-wasm
- +show-config --default --docs vs /usr/bin/ghostty (only the
build-specific gtk-opengl-debug line differs)