Improved Build Process and TypeScript 6 Support

[sweptsquash]

This pull request updates the build process and module configuration for the package, transitioning from tsc/tsc-alias to tsdown for building both ESM and CJS outputs. It also updates module entry points and dependencies to ensure better compatibility and modern standards.

Build system and module output changes:

• Switched the build script from using tsc and tsc-alias to tsdown, which now outputs both ESM and CJS formats. Added a new tsdown.config.ts file to configure the build process. [1] [2]
• Updated the main, module, and types fields in package.json to point to the correct ESM and CJS build outputs. Adjusted the exports field to properly map import/require paths for both formats.

Dependency updates:

• Upgraded several development dependencies (such as @types/node, typescript, oxlint, and others) to their latest versions for improved compatibility and tooling. Replaced tsc-alias with tsdown in the dev dependencies.