fix(devtools): stabilize Penpot MCP, fix S3 creds, OIDC registration

MCP server:
- Replace vite build --watch + livePreview with static vite preview
  (watch mode was reloading the plugin iframe, killing WebSocket)
- Bake WS_URI at Docker build time for production WebSocket URL
- Add server-side application-level keepalive messages every 25s
- Add client-side auto-reconnect with exponential backoff
- Set Pingora route timeout to 86400s for WebSocket idle tolerance

Penpot:
- Add AWS_ACCESS_KEY_ID/SECRET env vars for S3 SDK compatibility
- Set S3 region to satisfy AWS SDK credential chain
- Enable OIDC registration (disable-registration blocks OIDC signup)
- Fix frontend port (8080 not 80)
- Add penpot bucket to seaweedfs-buckets init job

base/devtools/penpot-mcp.Dockerfile

@@ -1,12 +1,12 @@
 FROM node:22-alpine
-RUN npm install -g pnpm@latest @penpot/mcp@latest && \
-    cd /usr/local/lib/node_modules/@penpot/mcp && \
-    pnpm -r install && \
-    pnpm run build
+ARG WS_URI=wss://mcp-designer.sunbeam.pt/ws
+RUN npm install -g pnpm@latest
+COPY . /opt/penpot-mcp/
+WORKDIR /opt/penpot-mcp
+RUN WS_URI=$WS_URI pnpm -r install && WS_URI=$WS_URI pnpm run build
 ENV PENPOT_MCP_REMOTE_MODE=true \
     PENPOT_MCP_SERVER_HOST=0.0.0.0 \
     PENPOT_MCP_SERVER_PORT=4401 \
     PENPOT_MCP_WEBSOCKET_PORT=4402
-EXPOSE 4401 4402
-WORKDIR /usr/local/lib/node_modules/@penpot/mcp
+EXPOSE 4400 4401 4402
 CMD ["pnpm", "run", "start"]