test(daemon): serialize SPACESH_SOCK-mutating lifecycle tests to fix env race

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

crates/spaceshd/src/lifecycle.rs

@@ -56,6 +56,7 @@ mod tests {
 
     #[test]
     fn paths_live_under_spacesh_dir() {
+        let _serial = crate::test_support::serial();
         let dir = spacesh_dir().unwrap();
         assert!(socket_path().unwrap().starts_with(&dir));
         assert!(lock_path().unwrap().starts_with(&dir));
@@ -75,8 +76,9 @@ mod tests {
 
     #[test]
     fn socket_path_honors_env_override() {
-        // Note: set/remove around the assertion; tests in this module run serially enough,
-        // but guard by restoring afterwards.
+        let _serial = crate::test_support::serial();
+        // Note: set/remove around the assertion; serialized against the other
+        // env-sensitive lifecycle test via the crate's serial() lock.
         std::env::set_var("SPACESH_SOCK", "/tmp/spacesh-test-override.sock");
         let p = socket_path().unwrap();
         std::env::remove_var("SPACESH_SOCK");