Add tsdown

[Minhir]

No description provided.

[Copilot]

Pull Request Overview

This PR migrates the build system from TypeScript Compiler (tsc) to tsdown, modernizing the build toolchain and package configuration. The project now outputs ES modules and uses a more contemporary build tool based on rolldown.

• Replaces TypeScript Compiler (tsc) with tsdown for building
• Updates package.json to properly support ES modules with "type": "module"
• Changes output directory from lib/ to dist/

Reviewed Changes

Copilot reviewed 3 out of 6 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
tsdown.config.ts	Adds configuration file for the tsdown build tool, specifying entry point and build options
tsconfig.json	Removes outDir option as build output is now managed by tsdown
package.json	Updates module system to ESM, changes build script from tsc to tsdown, updates output paths to dist/, adds tsdown dependency, and corrects repository URL format
package-lock.json	Adds tsdown and its dependencies (rolldown, babel plugins, oxc-project tools, etc.)
biome.json	Removes obsolete lib directory from file includes list
.gitignore	Changes ignored output directory from lib/ to dist/

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[Copilot]

The package exports both 'module' and 'main' fields pointing to the same file. With '"type": "module"', the 'main' field will be treated as an ES module. Consider adding a 'types' field in the exports map (e.g., '"types": "./dist/index.d.ts"') for better TypeScript integration, especially when using modern Node.js resolution.

Suggested change

	".": "./dist/index.js",
	".": {
	"import": "./dist/index.js",
	"require": "./dist/index.js",
	"types": "./dist/index.d.ts"
	},