Add release checklist, sync SLA, security response, channel command

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

bin/omarchy-cn-channel

@@ -0,0 +1,29 @@
+#!/bin/bash
+# omarchy:summary=Show or set the OmarchyCN release channel
+# omarchy:args=[stable|beta|nightly]
+# omarchy:examples=omarchycn channel | omarchycn channel beta
+
+set -euo pipefail
+
+CHANNEL_FILE="$HOME/.config/omarchycn/channel"
+
+if (( $# == 0 )); then
+  if [[ -f $CHANNEL_FILE ]]; then
+    cat "$CHANNEL_FILE"
+  else
+    echo "beta (default)"
+  fi
+  exit 0
+fi
+
+case "$1" in
+stable | beta | nightly)
+  mkdir -p "${CHANNEL_FILE%/*}"
+  echo "$1" > "$CHANNEL_FILE"
+  echo "Channel: $1"
+  ;;
+*)
+  echo "Unknown channel: $1 (stable|beta|nightly)" >&2
+  exit 1
+  ;;
+esac