[AdamPlatin123]

Issue

Fixes #679

The bug: in the 0.2.3 desktop app, every preview of a Word, Excel or PowerPoint file fails with 「读取失败：Office 转换失败，未生成可用的 PDF。请检查该文件后重试。」 on Windows (and, by the same code path, on macOS).

What changed / 改了什么

• Cause. The Host loads DSH from resources/app.asar. @deepseek-ai/libreoffice-kit resolves its engine package (require.resolve('@deepseek-ai/libreoffice-kit-<platform>/package.json')) and starts the program in it, so the engine's executable and program folder are paths inside app.asar. Electron cannot start a program by a path inside an archive, even an unpacked one: spawn … app.asar\node_modules\@deepseek-ai\libreoffice-kit-win32-x64\bin\libreoffice-kit.exe ENOENT. DSH maps this to the generic failed reason the preview shows.
• Fix. The asar stays. electron-builder.yml leaves only the engine packages (@deepseek-ai/libreoffice-kit-*) out of it and ships them as plain files in resources/node_modules (extraResources). Node's lookup from the kit inside app.asar/node_modules goes up to resources/node_modules and finds the engine at a real path. No change to DSH or the kit (AGENTS.md rule 1). On Linux, where the app is already plain files since dev's plain-Node Host, the engine moves from resources/app/node_modules to resources/node_modules and is found the same way.
• Packaged check. scripts/check-packed.mjs gains checkOffice, next to checkSharp: it writes a one-paragraph .docx into the throwaway folder and converts it to PDF with the packaged kit and engine, run the way the Host runs (plain Node on Linux, Electron's Node mode elsewhere), with the font cache in the throwaway folder, and checks the PDF header. CI runs it on Windows, macOS and Linux (WASM engine), after the build, after the install and after the update.
• Test. test/package.test.mjs checks, with electron-builder's own matchers, that the engine packages stay out of the app's files and go to resources/node_modules, and that the kit and other packages stay in.
• app/README.md says where the engine ships and why, and what check-packed now converts.

Why not asar: false. The first version of this pull request turned the asar off. On CI that made the Windows installer write 23,573 files: a fresh install took about 4 min 20 s instead of about 1 min, and the update step (uninstall, then install) ran past its 4-minute limit, which is the red Windows job on the earlier run. Locally the app also took about 7 s longer to show the Host page. Shipping only the engine as plain files keeps all of that as it is on dev.

Changelog

Office file previews (Word, Excel, PowerPoint) work again in the desktop app on Windows and macOS.

How I checked it / 怎么验证的

• By hand on Windows, Electron 44.7.0 in Node mode (as the Host): a real app.asar with the kit (unpacked as in asarUnpack) and the engine in resources/node_modules converts a .docx to PDF with the native engine. The same layout with the engine inside the asar fails with the ENOENT above.
• App tests (app/): test/package.test.mjs passes, and its new test fails against dev's electron-builder.yml. The other failures on this machine are local only: Node 22.14 lacks registerHooks and zstdCompressSync (CI uses Node 24), and one symlink test expects an EPERM that this machine does not raise.
• oxlint on the changed files.
• npm test, --check in ds-bot/: this pull request changes nothing there; CI runs them.
• npm run pack and check-packed locally: not run here (this machine's Node is older than the app needs). CI packs, checks, installs, updates and uninstalls on Windows, macOS and Linux.
• Smoke test, for changes to index.js or src/host/ / 改了 index.js 或 src/host/ 时跑冒烟测试 — not applicable.
• Screenshot attached, for interface changes / 界面改动已附截图 — not applicable.
• Seen on the way, not fixed here: the native engine also failed when its program folder path was 232 characters long, under the kit's 260-character workaround (Cannot open directory …/program/program/services). An install under %LOCALAPPDATA%\Programs\DS Bot is about 110 characters.

Checklist / 检查

• One issue, one subject. / 只做一件事。
• src/client/ changed → npm run build ran and client.js is committed. / 改了 src/client/ 就已重新 build 并提交 client.js。 (not changed)
• No keys, tokens or personal data, also in screenshots. / 没有密钥、token 或个人信息，截图里也没有。
• No AI tool as author or Co-authored-by. / 没有把 AI 工具写成作者或 Co-authored-by。

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