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>

internal/cmd/version.go

@@ -12,7 +12,7 @@ import (
 
 // Version information - set at build time via ldflags
 var (
-	Version = "0.3.0"
+	Version = "0.3.1"
 	// Build can be set via ldflags at compile time
 	Build = "dev"
 	// Commit and Branch - the git revision the binary was built from (optional ldflag)