Preview Client should support tsconfig path aliases

[taylor-lindores-reeves]

Goals

1. Streamline the developer workflow by integrating tsconfig path alias support directly into the Preview Client.
2. Remove the necessity for the current workaround script, reducing steps and potential for errors.
3. Introduce "bun" support for building packages in the email client to enhance performance.

Background

Currently, our Preview Client lacks support for tsconfig path aliases, which necessitates a manual workaround involving the execution of a custom script (preview:email) to normalize paths. This script reads and modifies the tsconfig paths to be relative to the .react-email directory. Moreover, the Preview Client does not support "bun", a fast all-in-one JavaScript runtime that could improve our build performance. This has become a bottleneck in our development process, as it requires stopping and rerunning processes which interrupts developer flow and affects productivity.

Proposal

The proposed solution involves two primary enhancements to the Preview Client:

1. Direct integration of tsconfig path alias resolution within the Preview Client's build process, making the use of the normalizeReactEmailPaths.mjs script below obsolete.

import * as fs from "fs";

const devServerTsConfig = JSON.parse(
	fs.readFileSync(".react-email/tsconfig.json").toString(),
);

const currentTsConfig = JSON.parse(fs.readFileSync("tsconfig.json").toString());

const normalizedPaths = Object.entries(
	currentTsConfig.compilerOptions.paths,
).reduce((prev, [key, paths]) => {
	prev[key] = paths.map(path => `../${path}`);
	return prev;
}, {});

devServerTsConfig.compilerOptions.paths = normalizedPaths;

fs.writeFileSync(
	".react-email/tsconfig.json",
	JSON.stringify(devServerTsConfig, null, 2),
);

2. Incorporate "bun" into the Preview Client's build toolchain for the email client to leverage its performance benefits over npm.

This will greatly simplify our project configuration and make our development process more efficient.