perf(plugin-dts): require typescript to improve startup performance

[chenjiahan]

Summary

Load typescript via require instead of import to avoid cjs-module-lexer overhead and improve startup performance.

The same as web-infra-dev/rsbuild#5673.

Before

After

Checklist

• Tests updated (or not required).
• Documentation updated (or not required).

[Copilot]

Pull Request Overview

This PR improves startup performance by loading TypeScript via require instead of import to avoid cjs-module-lexer overhead. Since TypeScript only provides a CommonJS bundle, using require eliminates the need for Node.js to parse it with cjs-module-lexer during module loading.

Key changes:

• Replace TypeScript default import with type-only imports and a require-based loader
• Add createRequire setup to enable CommonJS loading in ESM context
• Export the required TypeScript instance for use across the codebase

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
packages/plugin-dts/src/utils.ts	Implements the require-based TypeScript loader and exports ts instance
packages/plugin-dts/src/tsc.ts	Updates to use type-only imports and the shared ts instance
packages/plugin-dts/src/index.ts	Updates to use type-only imports and the shared ts instance

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