feat: add prepare script to ensure builds before publishing

[developerkunal]

Changes

This PR adds a prepare script to automatically build the package before publishing and optimizes CI workflows to eliminate duplicate builds.

What's changing:

• Added new prepare script to package.json that runs npm run build before publishing
• Updated CI workflows to use --ignore-scripts flag during dependency installation
• Set require-build: false in release workflow to prevent explicit builds

No breaking changes - end users installing the package are unaffected as they receive pre-built artifacts.

References

• npm prepare script documentation
• npm ignore-scripts documentation

Testing

This change can be tested by:

1. Verifying CI workflows run successfully with the new --ignore-scripts flag
2. Testing package publishing with npm publish --dry-run to ensure prepare script runs
3. Confirming build artifacts are correctly generated before publishing
4. Validating no functionality changes for end users installing the package

Testing performed:

• ✅ npm publish --dry-run confirmed prepare script builds package correctly

• ✅ npm ci --ignore-scripts confirmed dependencies install without running prepare script

• ✅ Verified no dependencies have critical postinstall scripts that would be affected

• This change adds unit test coverage - N/A (build infrastructure change)

• This change adds integration test coverage - N/A (build infrastructure change)

Checklist

• I have read the Auth0 general contribution guidelines
• I have read the Auth0 Code of Conduct
• All existing and new tests complete without errors