feat: implement Docker support with entrypoint script and environment configuration for data directory

.dockerignore

@@ -0,0 +1,21 @@
+# ignore node_modules, build artifacts, git metadata
+**/node_modules
+frontend/dist
+backend/node_modules
+.git
+.vscode
+.idea
+.env
+npm-debug.log*
+yarn-debug.log*
+pnpm-debug.log*
+Dockerfile*
+docker-compose*.yml
+
+# Do NOT include runtime backend data in the build context
+backend/data/
+backend/data/**
+
+# keep local dev artifacts out
+.DS_Store
+Thumbs.db