Set up Vite build

[bgins]

Summary

Problem

Browser extensions have incompatibilities across different browsers.

Impact

Targeting multiple browsers will be challenging to maintain manually.

Solution

Set up a build using Vite that emits builds that will work in each target browser. At the moment, the main incompatibility is that Firefox does not yet support service workers for Manifest V3 extensions.

Detail

Targeting multiple browsers is the primary motivation, but adding a build will also give us:

• Svelte support
• TypeScript support
• ESM support (in some of the extension scripts)