added engine seperation from posts and entrypoint for compose building

entrypoint.sh

@@ -0,0 +1,20 @@
+#!/bin/sh
+
+# Pass-through mode: if arguments were provided, execute them directly
+if [ "$#" -gt 0 ]; then
+	exec "$@"
+fi
+
+# Build static site from mounted or packaged markdown posts
+echo "[blog-engine] Compiling static site with Eleventy..."
+npm run build || exit 1
+
+# Optional watch mode for zero-restart live note updates
+if [ "${WATCH:-false}" = "true" ]; then
+	echo "[blog-engine] Starting live watch daemon for markdown changes..."
+	npx @11ty/eleventy --watch &
+fi
+
+# Start production static web server
+echo "[blog-engine] Starting static server on port ${PORT:-8080}..."
+exec node server.js