chore: Bump version to 0.4.0

Key fix: Orphan cleanup now skips Claude processes in valid Gas Town
tmux sessions (gt-*/hq-*), preventing false kills of witnesses,
refineries, and deacon during startup.

Updated all component versions:
- gt CLI: 0.3.1 → 0.4.0
- npm package: 0.3.0 → 0.4.0

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

internal/cmd/info.go

@@ -74,6 +74,13 @@ type VersionChange struct {
 
 // versionChanges contains agent-actionable changes for recent versions
 var versionChanges = []VersionChange{
+	{
+		Version: "0.4.0",
+		Date:    "2026-01-17",
+		Changes: []string{
+			"FIX: Orphan cleanup skips valid tmux sessions - Prevents false kills of witnesses/refineries/deacon during startup by checking gt-*/hq-* session membership",
+		},
+	},
 	{
 		Version: "0.3.1",
 		Date:    "2026-01-17",