git worktree remove: forceRequired is false on non-English locales

Description

Git.worktree.remove decides whether --force is required by matching git's stderr against English text (packages/core/src/git.ts):

forceRequired: operation === "remove" && /contains modified or untracked files|is dirty/i.test(message),

git localizes its diagnostics, so this only matches on an English system. With LANG=zh_CN.UTF-8 the same failure reads:

致命错误：'../wt' 包含修改或未跟踪的文件，使用 --force 删除

The regex misses, forceRequired becomes false, and callers lose the signal that retrying with --force would succeed. The user sees a bare failure instead of the hint.

git worktree remove has no --porcelain or other machine-readable output, so there is nothing structured to parse instead.

This also makes ProjectCopy > requires force to remove a dirty git worktree fail on any non-English machine, while passing on CI because runners default to an English locale.

Steps to reproduce

mkdir -p /tmp/wt && cd /tmp/wt && git init -q main && cd main
git -c user.email=a@b -c user.name=a commit -q --allow-empty -m init
git worktree add -q ../wt && echo dirty > ../wt/dirty.txt
LC_ALL=C git worktree remove ../wt     # English: "contains modified or untracked files"
LC_ALL=zh_CN.UTF-8 git worktree remove ../wt   # localized, regex no longer matches

Or from the repo, on a non-English system:

cd packages/core && bun test test/project-copy.test.ts

requires force to remove a dirty git worktree fails on expect(error.forceRequired).toBe(true).