feat: Drop requirement to have a user-provided babel config

[frankieyan]

This PR removes the need for users to provide a Babel config, as there is a wide range of ways the React Compiler babel plugin can be set up. Instead, this sets up a standalone Babel config solely focused on detecting compiler errors.

References

Closes #7

Test plan

Run the tool against the included fixtures:

• Run npm run build
• Navigate to src/__fixtures__/sample-project
• Run node ../../../dist/index.mjs --overwrite
• It reports errors in the files and creates a .react-compiler.rec.json in src/__fixtures__/sample-project/src

[doistbot-app]

The changes successfully implement the goal of making the tool standalone by internalizing Babel dependencies and removing the need for a user-provided configuration. The documentation and lockfile updates are consistent with this architectural shift.