Add omarchycn CLI entry and cn command group

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QKxGW1raAWaqeU8WdHsMsp

bin/omarchy-cn-version

@@ -0,0 +1,13 @@
+#!/bin/bash
+# omarchy:summary=Show the OmarchyCN version
+# omarchy:examples=omarchycn version
+
+set -euo pipefail
+
+OMARCHY_BIN_DIR=$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd)
+ROOT="${OMARCHY_BIN_DIR%/bin}"
+
+upstream=$(<"$ROOT/version")
+release=$(<"$ROOT/cn/release")
+
+echo "${upstream}-cn.${release}"