chore: flatten src/ to root

utils/shell/resolveDefaultShell.ts

@@ -0,0 +1,14 @@
+import { getInitialSettings } from '../settings/settings.js'
+
+/**
+ * Resolve the default shell for input-box `!` commands.
+ *
+ * Resolution order (docs/design/ps-shell-selection.md §4.2):
+ *   settings.defaultShell → 'bash'
+ *
+ * Platform default is 'bash' everywhere — we do NOT auto-flip Windows to
+ * PowerShell (would break existing Windows users with bash hooks).
+ */
+export function resolveDefaultShell(): 'bash' | 'powershell' {
+  return getInitialSettings().defaultShell ?? 'bash'
+}