Expose native MCP endpoint alongside mcpo

Run supergateway on port 8080 (streamable HTTP at /mcp) next to mcpo on
8000, each spawning its own webfetch-mcp child. Supervise both under tini.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

Dockerfile

@@ -18,6 +18,12 @@ ARG MCPO_VERSION=0.0.20
 # release's uv.lock for its actual tested "mcp" version and update this too.
 ARG MCP_SDK_VERSION=1.17.0
 
+# Pinned supergateway release (npm). It serves a stdio MCP server as a native
+# streamable-HTTP endpoint. Bump by checking the new version's CLI flags still
+# match what entrypoint.sh assumes (--stdio/--outputTransport/--port/
+# --healthEndpoint).
+ARG SUPERGATEWAY_VERSION=4.1.0
+
 FROM python:3.12-slim-bookworm AS vendor
 ARG WEBFETCH_MCP_COMMIT
 RUN apt-get update && apt-get install -y --no-install-recommends git \
@@ -31,19 +37,26 @@ RUN mkdir /vendored \
 FROM python:3.12-slim-bookworm
 ARG MCPO_VERSION
 ARG MCP_SDK_VERSION
+ARG SUPERGATEWAY_VERSION
 
+# tini is PID 1: entrypoint.sh supervises two long-running processes, so
+# something needs to reap zombies and deliver signals properly.
 # Node.js 22, matching the version mcpo's own official image is built and
 # tested against (webfetch-mcp only requires >=18).
 RUN apt-get update && apt-get install -y --no-install-recommends \
         curl \
         ca-certificates \
         gnupg \
+        tini \
     && curl -fsSL https://deb.nodesource.com/setup_22.x | bash - \
     && apt-get install -y --no-install-recommends nodejs \
     && rm -rf /var/lib/apt/lists/*
 
 RUN pip install --no-cache-dir "mcpo==${MCPO_VERSION}" "mcp==${MCP_SDK_VERSION}"
 
+RUN npm install -g --omit=dev "supergateway@${SUPERGATEWAY_VERSION}" \
+    && npm cache clean --force
+
 COPY --from=vendor /vendored /app/webfetch-mcp
 WORKDIR /app/webfetch-mcp
 RUN npm ci --omit=dev
@@ -51,5 +64,5 @@ RUN npm ci --omit=dev
 COPY entrypoint.sh /entrypoint.sh
 RUN chmod +x /entrypoint.sh
 
-EXPOSE 8000
-ENTRYPOINT ["/entrypoint.sh"]
+EXPOSE 8000 8080
+ENTRYPOINT ["tini", "--", "/entrypoint.sh"]