Bring repo up to REPO_POLICIES.md standards

- Add prettier (4-space indents) and reformat all files
- Add Makefile with test/lint/fmt/fmt-check/check/docker targets
- Add MIT LICENSE file
- Add REPO_POLICIES.md
- Fix Dockerfile: listen on 8080 with PORT env var via envsubst
- Restructure README.md with all required sections
- Set up pre-commit hook (make check)
- Update .prettierignore, .gitignore, .dockerignore

Makefile

@@ -0,0 +1,18 @@
+.PHONY: test lint fmt fmt-check check docker
+
+test:
+	timeout 30 yarn build
+
+lint:
+	yarn prettier --check .
+
+fmt:
+	yarn prettier --write .
+
+fmt-check:
+	yarn prettier --check .
+
+check: test lint fmt-check
+
+docker:
+	timeout 300 docker build -t netwatch .