Add Dockerfile for Node.js 22 runtime

[Copilot]

Adds Docker support for running the proxy-fetch-server in a containerized environment using Node.js 22.

Changes

• Dockerfile: Node.js 22 base image with TypeScript build pipeline

  • Uses npm ci for reproducible dependency installation
  • Builds source files via tsc
  • Runs server via npx @humanwhocodes/proxy-fetch-server
  • Exposes port 8080 (configurable via PORT env var)

• .dockerignore: Excludes dev artifacts, tests, and build files from container image

• README.md: Added Docker usage section with build/run examples

Usage

docker build -t proxy-fetch-server .

docker run -p 8080:8080 \
  -e PROXY_FETCH_KEY=secret \
  -e PROXY_URI=http://proxy.example.com:8080 \
  proxy-fetch-server

Required environment variables: PROXY_FETCH_KEY, PROXY_URI
Optional: PORT (default 8080), PROXY_TOKEN

Original prompt

Create a Dockerfile that can run npx @humanwhocodes/proxy-fetch-server inside. It should use Node.js 22.

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