Have the MarkItDown MCP server read MARKITDOWN_ENABLE_PLUGINS from ENV (#1273)

* Have the MarkItdown MCP server read MARKITDOWN_ENABLE_PLUGINS from os.environ

* Update the Dockerfile to enable plugins. No puglins are installed by default.

packages/markitdown-mcp/Dockerfile

@@ -3,8 +3,10 @@ FROM python:3.13-slim-bullseye
 ENV DEBIAN_FRONTEND=noninteractive
 ENV EXIFTOOL_PATH=/usr/bin/exiftool
 ENV FFMPEG_PATH=/usr/bin/ffmpeg
+ENV MARKITDOWN_ENABLE_PLUGINS=True
 
 # Runtime dependency
+# NOTE: Add any additional MarkItDown plugins here
 RUN apt-get update && apt-get install -y --no-install-recommends \
     ffmpeg \
     exiftool