workHubHelp copy disagrees across en, zh-CN, and zh-TW

## What happened

`workHubHelp` in `apps/desktop/src/renderer/locales/settings-preferences-copy.ts` says three different things across the three locales, and the two versions describe *opposite* situations — one says the feature is unusable, the other describes what it does.

| locale | line | value |
|---|---:|---|
| `zh-CN` | 336 | WorkHub 目前仍不可用。此开关仅供开发测试，开启后也不能保证正常使用。 |
| `zh-TW` | 435 | 在一個入口檢視已有工作，並將新輸入保守地送往普通任務。 |
| `en` | 491 | WorkHub is not available yet. This toggle is for development testing and does not enable a usable feature. |

I do not know which one is right, and that is the question here. Either WorkHub is still unavailable and the `zh-TW` string needs replacing, or it has since become usable and it is `en`/`zh-CN` that are stale. Someone who knows the current state of the feature has to say which.

## How to reproduce

```bash
grep -o "workHubHelp: '[^']*'" apps/desktop/src/renderer/locales/settings-preferences-copy.ts
```

Then open Settings → Chat defaults with the interface language set to each of the three locales and compare the help text under the WorkHub toggle.

## Environment

Not runtime-specific. Present on `main` and on `stack/i18n-ko-core`; the strings above are read from `a193ad8d1`.

## Logs, screenshots, or additional context

### How the three came apart

Nobody did anything wrong here — it is ordinary merge-order drift between two pull requests:

- #3935 (`feat(workhub): persist delegation linkage`, merged 2026-08-28) rewrote `workHubHelp` for `en` and `zh-CN`. Before it, `en` read “See existing work in one entry and conservatively route new input to ordinary tasks.” and `zh-CN` read “在一个入口查看已有工作，并将新输入保守地送往普通任务。”
- #3853 (`feat(i18n): add Traditional Chinese locale`, merged 2026-09-04) added the `zh-TW` catalog. Its `workHubHelp` is a faithful Traditional-Chinese rendering of the pre-#3935 `zh-CN` text, character for character.

So #3853 branched before #3935 landed, translated the copy that was current at the time, and merged a week later. Git does not flag that as a conflict, because the two pull requests touched different lines of the same object.

The chronology is worth stating plainly, because it cuts the other way from what a reader might assume: `zh-TW` is the **most recently committed** of the three, so “the newest one is right” does not settle it either.

### Scope

`workHubHelp` is the only key affected. #3935 changed exactly two lines in this file, and comparing every key on those lines before and after shows `workHubHelp` as the only entry whose value differs — 14 keys on the `zh-CN` line and 44 on the `en` line are otherwise identical.

### Why this is being filed separately

Found while building the Korean glossary for #3977 (desktop slice 1), which covers this file. It is out of that issue's scope — slice 1 adds a `ko` catalog and does not change existing locales — and resolving it needs a product answer about WorkHub rather than a translation decision, so it should not be folded into a translation pull request.

Once the intended wording is settled I am happy to fix it, including the `ko` string, so slice 1 does not add a fourth variant.

cc @AcerYue0, who wrote the `zh-TW` catalog in #3853 and will know what the source text looked like at that point.

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*Claude Opus 5 assisted with the investigation and this write-up. Every line number, commit, and string above was read from a local checkout.*