fix(build): run Windows NSIS packaging inside docker; add artifact size gate

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.

cmd/gui/docker/win-builder/Dockerfile

@@ -1,11 +1,20 @@
 # ModelRouter GUI Windows builder
-# Self-sufficient cross-compilation environment for the embedded llmsproxy core.
-# Produces llmsproxy.exe (Go, windows/amd64, luajit tag) + lua51.dll (LuaJIT mingw build)
-# inside a mounted workspace: cmd/gui/bin/{llmsproxy.exe,lua51.dll}
+# Self-sufficient cross-compilation environment for the embedded llmsproxy core
+# AND for packaging the Windows NSIS installer.
+#
+# Produces inside a mounted workspace:
+#   - llmsproxy.exe (Go, windows/amd64, luajit tag) + lua51.dll
+#   - ModelRouter Setup <ver>.exe  (electron-builder --win nsis; requires wine
+#     so the uninstaller is generated — set USE_SYSTEM_WINE=true)
 #
 # Build:   docker build -t modelrouter/win-builder cmd/gui/docker/win-builder
 # Usage:   make gui-win-docker   (or cmd/gui/scripts/dist-win-docker.sh)
 #
+# This image is the SINGLE wine provider for the NSIS step, so a host that has
+# no / broken wine (e.g. amd64-only Debian: no syswow64 -> c0000135) can still
+# produce a real installer. The NSIS step MUST run inside this image; running it
+# on the host was how the 1.3.0 264 KB degenerate exe got shipped.
+#
 # LuaJIT source is fetched from gitcode.com (CN-reachable mirror) with github
 # fallback; pass --build-arg LUAJIT_REPO to override.
 
@@ -13,11 +22,24 @@ FROM golang:1.25
 
 ARG LUAJIT_REPO=https://gitcode.com/openresty/luajit2.git
 
-RUN apt-get update -qq \
+# i386 arch is required for wine32 (the NSIS uninstaller step runs a win32 exe
+# through wine's wow64 path, which needs the 32-bit runtime under /usr/lib/i386).
+RUN dpkg --add-architecture i386 \
+ && apt-get update -qq \
  && DEBIAN_FRONTEND=noninteractive apt-get install -y -qq \
       gcc-mingw-w64-x86-64 make ca-certificates git \
+      # NSIS step needs node + the electron-builder toolchain
+      nodejs npm \
+      # wine (32+64) for generating the NSIS uninstaller
+      wine64 wine32:i386 \
  && rm -rf /var/lib/apt/lists/*
 
+# electron-builder resolves the uninstaller via the system wine when
+# USE_SYSTEM_WINE=true (or by default on Linux without a toolset). Pin it.
+ENV USE_SYSTEM_WINE=true
+ENV WINEDEBUG=-all
+ENV ELECTRON_BUILDER_CACHE=/workspace/cmd/gui/.cache
+
 # LuaJIT cross-compiled for Windows; keeps lua51.dll and the cgo import lib
 # (libluajit-5.1.dll.a -> libluajit-5.1.a in the mingw lib dir).
 # NOTE: $LUAJIT_REPO deliberately unquoted in "sh -c" — quoting the ARG would

cmd/gui/scripts/dist-win-docker.sh

@@ -1,23 +1,64 @@
 #!/usr/bin/env bash
-# One-shot Windows release build for the GUI:
+# One-shot Windows release build for the GUI — ENTIRELY inside docker.
+#
 #   1) cross-compile the embedded core in docker (llmsproxy.exe + lua51.dll)
-#   2) host-side electron-builder NSIS packaging (wine required on host)
+#   2) electron-builder NSIS packaging ALSO inside docker (wine for the
+#      uninstaller step lives in the image — see Dockerfile). This is the fix
+#      for the 1.3.0/1.4.0 broken installers: the host had amd64-only wine
+#      (no syswow64 -> c0000135), which made electron-builder silently emit a
+#      264 KB degenerate exe without its 86 MB payload.
+#
 # Outputs: cmd/build/gui-dist/"ModelRouter Setup <version>.exe"
+#          cmd/build/gui-dist/modelrouter-gui-<version>-x64.nsis.7z
+#
+# Needs:   docker (any machine; no host mingw/wine/node required)
 set -euo pipefail
 
 ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/../../.." && pwd)"
-cd "$ROOT/cmd/gui"
+IMAGE="${WIN_BUILDER_IMAGE:-modelrouter/win-builder}"
+PROXY="${GOPROXY:-https://goproxy.cn,direct}"
+CACHE_VOL="modelrouter-eb-cache"
 
-# 1) core (docker)
-"$ROOT/cmd/gui/scripts/win-core-docker.sh"
+command -v docker >/dev/null || { echo "docker required"; exit 1; }
 
-# 2) packaging (host, needs wine for electron-builder's signtool/nsis)
-command -v wine >/dev/null || { echo "wine required on host for NSIS packaging"; exit 1; }
-if ! command -v npx >/dev/null; then echo "node/npm required"; exit 1; fi
+if ! docker image inspect "$IMAGE" >/dev/null 2>&1; then
+  echo "[dist-win-docker] building image $IMAGE (first run, ~5-10 min)..."
+  docker build -t "$IMAGE" "$ROOT/cmd/gui/docker/win-builder"
+fi
 
-echo "[dist-win] electron-builder --win nsis ..."
-# bin artifacts already refreshed by win-core-docker.sh; skip the prepare step
-npx electron-builder --win nsis
+docker volume create "$CACHE_VOL" >/dev/null 2>&1 || true
 
-ls -la "$ROOT/cmd/build/gui-dist/"*.exe 2>/dev/null
-echo "[dist-win] done"
+# 1) embedded core + 2) NSIS packaging — both inside the image so wine and node
+# are the image's, never the host's. electron-builder downloads electron + nsis
+# toolchains into ~/.cache on first run; the mounted volume keeps that warm so
+# subsequent builds are incremental instead of re-fetching ~400 MB.
+echo "[dist-win-docker] cross-compiling core + electron-builder NSIS in docker ..."
+docker run --rm \
+  -v "$ROOT":/workspace \
+  -v "$CACHE_VOL":/root/.cache \
+  -e GOPROXY="$PROXY" \
+  -w /workspace \
+  "$IMAGE" bash -c '
+    set -euo pipefail
+    cp /opt/luajit2/src/lua51.dll /workspace/cmd/gui/bin/lua51.dll
+    GOOS=windows GOARCH=amd64 CGO_ENABLED=1 CC=x86_64-w64-mingw32-gcc \
+      go build -buildvcs=false -tags luajit -trimpath \
+      -o /workspace/cmd/gui/bin/llmsproxy.exe ./cmd/llmsproxy
+    echo "  -> core built"
+    # wine needs one prefix initialization so its wow64 runtime (syswow64/ntdll)
+    # exists — the exact thing that was missing on the broken host. Use a shared
+    # prefix in the cache volume so it is initialized only on the first run.
+    export WINEPREFIX=/root/.cache/wineprefix
+    if [ ! -f "$WINEPREFIX/drive_c/windows/syswow64/ntdll.dll" ]; then
+      echo "  -> initializing wine prefix (first run)"
+      WINEDEBUG=-all wineboot -i || true
+    fi
+    cd /workspace/cmd/gui
+    # node_modules ships in the repo (host npm install already ran); reuse it.
+    npx electron-builder --win nsis
+  '
+
+echo "[dist-win-docker] verifying artifacts ..."
+"$ROOT/packaging/verify-dist.sh" "$ROOT/cmd/build/gui-dist"
+
+echo "[dist-win-docker] done"