fix(test): register pdu_test_skip_fs_errors in check-cfg

The #[allow(unexpected_cfgs)] approach doesn't override -D warnings
used in CI release builds. Register the custom cfg in Cargo.toml's
[lints.rust] section instead, which properly declares it as a known
cfg to the compiler.

https://claude.ai/code/session_01Ki7wbrgQXWs2GXf8h2hybQ

Author: claude

Cargo.toml

@@ -83,6 +83,9 @@ terminal_size = "0.4.3"
 text-block-macros = "0.2.0"
 zero-copy-pads = "0.2.0"
 
+[lints.rust]
+unexpected_cfgs = { level = "warn", check-cfg = ['cfg(pdu_test_skip_fs_errors)'] }
+
 [dev-dependencies]
 build-fs-tree = "0.8.1"
 command-extra = "1.0.0"

tests/cli_errors.rs

@@ -106,7 +106,6 @@ fn max_depth_0() {
 }
 
 #[cfg(unix)]
-#[allow(unexpected_cfgs)]
 #[cfg(not(pdu_test_skip_fs_errors))]
 #[test]
 fn fs_errors() {