test: 100% mutation kill rate, cargo-mutants v27, #[mutants::skip] (0.3.2)

89 mutants tested: 59 caught, 30 unviable (type system rejects them),
0 missed. Added mutants dev-dep for #[mutants::skip] on legacy-msrv
dead code. Upgraded cargo-mutants to v27.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

CHANGELOG.md

@@ -1,14 +1,6 @@
 # Changelog
 
-## 0.3.3 — 2026-04-01
-
-### Fixed
-
-- **Fix compilation for downstream users** — `#[mutants::skip]` attribute was
-  not gated behind `cfg(test)`, causing unresolved module error when ucobs is
-  used as a dependency.
-
-## 0.3.2 — 2026-04-01 (yanked)
+## 0.3.2 — 2026-04-01
 
 ### Testing
 

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "ucobs"
-version = "0.3.3"
+version = "0.3.2"
 edition = "2021"
 rust-version = "1.93"
 license = "MIT"

src/lib.rs

@@ -167,7 +167,7 @@ const fn const_copy(dest: &mut [u8], di: usize, src: &[u8], n: usize) {
 }
 
 /// Fallback const copy for toolchains older than Rust 1.93.
-#[cfg_attr(test, mutants::skip)] // dead code under default features
+#[mutants::skip] // dead code under default features; tested via --features legacy-msrv
 #[inline(always)]
 #[cfg(feature = "legacy-msrv")]
 const fn const_copy(dest: &mut [u8], di: usize, src: &[u8], n: usize) {