[2.1.x] Migrate from CommonJS (CJS) to ECMAScript Modules (ESM)

[Tommytrg]

We need to transition our codebase from CommonJS (CJS) to ECMAScript Modules (ESM) to align with modern JavaScript standards, improve compatibility with the latest Node.js versions, and enable better tree-shaking for optimized builds.

• Update package.json to "type": "module" (or adjust file extensions accordingly).
• Refactor all require statements to import syntax.
• Update module.exports to export syntax.
• Identify and resolve any dependencies that don’t support ESM.
• Update build and testing configurations if necessary.
• Verify that all scripts and tools (e.g., bundlers, linters) work correctly with ESM.

Additional Context

• If we need dual support (CJS + ESM), we may consider using "exports" field in package.json.
• Some dependencies may still require dynamic imports (import() instead of require).