feat: persist compact session state

shared/hooks/scripts/show-session-state-pointer.sh

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+set -euo pipefail
+root=$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")/../.." && pwd)
+[ -f "$root/.ai-session/state.json" ] && printf 'Task state is available in .ai-session/state.json; read it only if needed.\n'