Add Docker support and rewrite the installation guide

[maarkN]

What

• Docker: multi-stage Dockerfile (+ .dockerignore). The build stage compiles the SDK; the runtime stage ships a lean image bundling Node 22, Python 3 and cloudscraper in an isolated venv, running as a non-root user. docker run -i --rm cloudscraper-js boots the MCP server in a single command.
• Docs: rewrote INSTALLATION.md to drop the stale auto-install / postinstall narrative (removed in 0.2.0) in favor of explicit pip / venv / helper paths, added a Docker section, and added a Docker pointer to the README.

Why

INSTALLATION.md still described the privileged auto-install on postinstall that was removed for security in 0.2.0 — contradicting both the README and package.json. The project also had no container image despite needing Node and Python 3 at runtime, so there was no one-command way to run the stack (or the MCP server) in a clean environment.

Verification

• docker build succeeds; the cloudscraper import is checked at build time.
• In-container smoke tests:
  • Python 3 + cloudscraper reachable as the non-root user (uid 1000) via the venv on PATH.
  • SDK loads under Node with all exports (createScraper, MCP, LangChain tool, function schemas, markdown).
  • End-to-end Node⇄Python daemon ping returns {"ok":true,"pong":true,"cloudscraper":true}.
• Image size ~484 MB.

Commits

• chore(docker): add container image with Node, Python and cloudscraper
• docs(install): rewrite guide for opt-in setup and document Docker