上一提交只改了 prepare-core.js（npm run core:win 路径），而 docker 构建走的是
dist-win-docker.sh 里的内联 go build，产物里的内嵌核心仍是 17.8MB 带调试符号。
两处必须同步，否则"用哪种方式构建"会决定包大小：现在 Linux 与 Windows 的内嵌
核心都剥符号。
The Windows installer has been broken since 1.3.0: electron-builder's NSIS step
needs wine to generate the uninstaller, but the host's wine was amd64-only (no
i386 runtime -> empty syswow64 -> `error c0000135`), so electron-builder silently
wrote a 264 KB installer shell with no payload. No check caught it and the broken
exe shipped. 1.4.0 reproduced the same failure this session.
Two fixes:
1. win-builder image gains node + wine32/wine64 (+ i386 arch). dist-win-docker.sh
now runs BOTH the core cross-build and `npx electron-builder --win nsis`
inside docker (USE_SYSTEM_WINE=true -> the image's wine). The wine prefix is
initialized on first run in the shared cache volume, so syswow64/ntdll.dll
exists - the exact thing the host lacked. The host needs no mingw/wine/node.
2. packaging/verify-dist.sh: a size-floor gate for GUI artifacts (exe >= 5 MB,
deb/rpm/nsis.7z >= 10 MB). Wired into `make gui-dist` and `make gui-win-docker`
and the dist-win-docker script, so a degenerate installer fails the build
instead of reaching a Release. Verified: it rejects the 264 KB exe and passes
the healthy artifacts.
