WXT: build fails when the project's path contains +

A minimal reproduction for a WXT 0.21 bug. wxt build fails when the project's absolute path contains +, such as a git worktree named after a branch with a slash (sync/foo → sync+foo):

ERROR  Cannot read properties of undefined (reading 'get')

The same project builds in a path without +.

Steps

git clone https://github.com/namuorg/wxt-plus-path-repro wxt+plus
cd wxt+plus
npm install
npx wxt build    # ERROR  Cannot read properties of undefined (reading 'get')

cd ..
git clone https://github.com/namuorg/wxt-plus-path-repro wxt-plain
cd wxt-plain
npm install
npx wxt build    # ✔ Built extension

Cause

removeEntrypointMainFunction (packages/wxt/src/internal/builders/vite/plugins/remove-entrypoint-main-function.ts) filters on new RegExp(^${absPath}$) without escaping the path. The t+ in wxt+plus is read as a quantifier, so the filter never matches entrypoints/content.ts, and its imports aren't removed when WXT imports it to read its options. Vite's module runner then loads assets/style.css, and Vite's CSS plugin crashes, since its CSS modules cache is only set up in buildStart.

WXT 0.20.11 compared id === absPath and built this project in either path.