Updates dependencies and migrates project to ESM

[milanholemans]

No description provided.

[Copilot]

Pull request overview

Migrates the project to ESM and updates the build/lint/tooling stack accordingly.

Changes:

• Switch TypeScript compilation to modern ESM (NodeNext) and update internal imports to use .js extensions.
• Replace ncc packaging with an esbuild-based bundling step to dist/index.js.
• Refresh dependencies/dev tooling and introduce a flat ESLint config.

Reviewed changes

Copilot reviewed 9 out of 15 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
tsconfig.json	Updates TS target/libs and switches module + resolution to NodeNext for ESM builds.
src/validate.ts	Updates ESM import path; reformats validation logic.
src/validate.spec.ts	Updates ESM import path; reformats tests.
src/utils.ts	Updates ESM import path; reformats helper utilities.
src/utils.spec.ts	Updates ESM import paths; reformats tests.
src/main.ts	Updates ESM import paths; reformats main action entrypoint.
src/constants.ts	Reformats exported constants object.
src/commands.ts	Updates ESM import paths; reformats command builders.
src/commands.spec.ts	Updates ESM import paths; reformats tests.
package.json	Marks package as ESM, replaces packaging script with esbuild, adds lint scripts, bumps deps/devDeps.
package-lock.json	Lockfile updated to reflect new dependency graph/tooling.
eslint.config.mjs	Adds ESLint flat config for TS + stylistic rules.
dist/sourcemap-register.js	Removes previously committed sourcemap registration artifact.

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