chore: add Apache-2.0 LICENSE and include it in published package

[jonathannorris]

Summary

• Adds the Apache-2.0 LICENSE file at the repo root (matching all other OpenFeature JS repos)
• Updates packages/js-ofrep-worker/package.json to include LICENSE in the published npm tarball via a prepack script (same pattern as js-sdk)

Details

The repo declared "license": "Apache-2.0" in both package.json files but had no actual LICENSE file. This is needed before publishing to npm.

The prepack script uses shx cp ../../LICENSE ./LICENSE to copy the root LICENSE into the package directory at pack time, following the js-sdk convention.

[gemini-code-assist]

Code Review

This pull request adds the Apache License 2.0 to the repository and updates the js-ofrep-worker package to include the license file in its distribution. A prepack script was added to copy the license from the root into the package directory. The reviewer suggested adding a postpack script to remove the copied license file after the packing process to maintain a clean workspace.

[gemini-code-assist]

The prepack script copies the root LICENSE file into the package directory, but there is no corresponding cleanup. This leaves an untracked LICENSE file in the package folder after running npm pack or npm publish. Adding a postpack script ensures the temporary file is removed, keeping the repository clean.

Suggested change

	"prepack": "shx cp ../../LICENSE ./LICENSE",
	"prepack": "shx cp ../../LICENSE ./LICENSE",
	"postpack": "shx rm ./LICENSE",