chore: release v0.3.1

### Fixed
- Orphan cleanup on macOS - TTY comparison now handles macOS '??' format
- Session kill orphan prevention - gt done and gt crew stop use KillSessionWithProcesses

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

CHANGELOG.md

@@ -7,6 +7,13 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [0.3.1] - 2026-01-17
+
+### Fixed
+
+- **Orphan cleanup on macOS** - Fixed TTY comparison (`??` vs `?`) so orphan detection works on macOS
+- **Session kill leaves orphans** - `gt done` and `gt crew stop` now use `KillSessionWithProcesses` to properly terminate all child processes before killing the tmux session
+
 ## [0.3.0] - 2026-01-17
 
 ### Added