Update plan and add install script

scripts/install.sh

@@ -0,0 +1,20 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+# Yonexus install script
+# - Registers plugin name: yonexus
+# - Places build output in dist/yonexus
+
+ROOT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+DIST_DIR="$ROOT_DIR/dist/yonexus"
+
+mkdir -p "$DIST_DIR"
+
+# Build step placeholder (replace with actual build command when ready)
+# e.g., npm run build
+
+# Example: copy plugin manifest and compiled assets into dist/yonexus
+# cp -r "$ROOT_DIR/plugin.json" "$DIST_DIR/"
+# cp -r "$ROOT_DIR/dist-build/*" "$DIST_DIR/"
+
+echo "[yonexus] install complete -> $DIST_DIR"