refactor!: Convert to ESM package

[avaly]

BREAKING CHANGE: Published as an ESM package. Requires node.js >=22.12.0.

Since 2024 the require(esm) feature has been enabled by default in the most recent node.js LTS versions. We can now safely ship only ESM sources in our NPM package without breaking any consumers.

[Copilot]

Pull request overview

This PR converts the package from a dual ESM/CommonJS distribution to an ESM-only package, leveraging Node.js's require(esm) feature introduced in recent LTS versions (20.19.0+ and 22.12.0+).

Changes:

• Removed CommonJS build output and configuration, keeping only ESM distribution
• Updated all TypeScript source files to use explicit .ts extensions in import statements
• Separated type-only imports using import type syntax for better ESM compatibility
• Updated TypeScript compiler configurations to use nodenext module resolution and modern ESM features

Reviewed changes

Copilot reviewed 29 out of 30 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
package.json	Updated Node.js engine requirements to require modern LTS versions; removed CJS exports and main entry point; simplified build script
tsconfig.json	Added ESM-specific compiler options including allowImportingTsExtensions, rewriteRelativeImportExtensions, and verbatimModuleSyntax; updated to use nodenext module resolution
tsconfig-esm.json	Updated module and target to use lowercase nodenext and esnext for consistency
tsconfig-cjs.json	Deleted as CJS builds are no longer generated
tests/ts/tsconfig.json	Updated target to es2023 and module casing to lowercase
src/**/*.ts	Added .ts extensions to all relative imports; separated type-only imports using import type; removed obsolete eslint disable comments
src/tests/**/*.test.ts	Updated imports to use .ts extensions and separated type-only imports
example/**/*.ts	Updated all example imports to use .ts extensions
build.sh	Removed as the build process is now a simple TypeScript compilation without post-processing

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