[CDX-468] Add modern ESM build

[esezen]

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[Copilot]

Pull request overview

Adds an ESM build output alongside the existing CommonJS + bundled browser build, and wires it into test and release workflows so the project can ship “modern” ESM artifacts (npm module entry + CDN .esm.js).

Changes:

• Add esbuild-based ESM outputs: lib/esm/constructorio.js (for npm) and dist/esm/*.esm.js (for CDN).
• Add a dedicated bundled-ESM test path that uses a test-only IIFE artifact for jsdom execution.
• Update CI/workflows to run bundled ESM tests and publish the ESM bundle to the CDN.

Reviewed changes

Copilot reviewed 8 out of 9 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
spec/src/utils/jsdom-global.js	Selects the appropriate bundle artifact for bundled tests (legacy vs ESM variant).
spec/src/modules/quizzes.js	Updates bundled quiz tests to load the correct artifact for the ESM variant.
scripts/bundle-esm.js	New script producing the CDN ESM bundle in dist/esm.
scripts/build-test-iife.js	New script producing a test-only IIFE bundle used for bundled ESM tests.
scripts/build-esm.js	New script producing the npm ESM entrypoint under lib/esm.
package.json	Adds module entry and hooks ESM builds into postcompile/postbundle; adds bundled-ESM test scripts.
.gitignore	Ignores dist/test-only/ artifacts.
.github/workflows/run-tests-bundled-esm.yml	New workflow running the bundled ESM test suite in CI.
.github/workflows/publish-cdn.yml	Publishes the new dist/esm artifact to S3 (versioned + latest).

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[constructor-claude-bedrock]

Code Review

This PR adds a modern ESM build output (lib/esm/ for npm, dist/esm/ for CDN) alongside the existing IIFE bundle, with a corresponding GitHub Actions workflow and a clever IIFE shim to keep JSDOM-based bundled tests working.

Inline comments: 7 discussions added

Overall Assessment: ⚠️ Needs Work