fix(gui): strip host LD_LIBRARY_PATH from packaging + defensive GPU/icon fixes

Root cause of the packaged GUI crashing with SIGSEGV inside ld.so on user
machines (segfault at fixed +0x1ff36, undefined symbols nspr_use_zone_allocator
/ localtime64): the build host had LD_LIBRARY_PATH polluted by a third-party
runtime (/opt/cangjie), which electron-builder baked into the produced binary's
dependency resolution. Clean machines without that library then fail in the
dynamic loader before any app code runs.

- Makefile: every gui-* pack target now runs under `env -u LD_LIBRARY_PATH`
- main.js: app.disableHardwareAcceleration() before ready (avoids the common
  Chromium GPU-process SIGSEGV on hybrid-GPU/Wayland Linux hosts)
- main.js: window icon reads from process.resourcesPath (real file, not asar)
  — asar-path icons are a known GTK segfault source on Linux

cmd/gui/main.js

@@ -47,6 +47,15 @@ const CORE_EXE = path.join(
   "bin",
   process.platform === "win32" ? "llmsproxy.exe" : "llmsproxy",
 );
+// Packaged window icon: must be a REAL file on disk (extraResource), not an
+// asar path — Electron/GTK pulls BrowserWindow icons from the filesystem and
+// crashes (SIGSEGV) when given an asar virtual path on Linux.
+// Dev:  cmd/gui/build/icon.png.
+const WINDOW_ICON = path.join(
+  app.isPackaged ? process.resourcesPath : __dirname,
+  "build",
+  "icon.png",
+);
 // default port for the embedded core (configurable via settings)
 const DEFAULT_PORT = 8787;
 
@@ -508,8 +517,9 @@ function createWindow() {
   const menu = Menu.buildFromTemplate([]);
   Menu.setApplicationMenu(menu);
   mainWindow = new BrowserWindow({
-    // Window icon (taskbar/dock): same asset as the tray and package.
-    icon: path.join(__dirname, "build", "icon.png"),
+    // Window icon (taskbar/dock). Packaged: real file under resourcesPath (see
+    // WINDOW_ICON) — an asar path here makes GTK segfault on Linux.
+    icon: WINDOW_ICON,
     // GNOME taskbar icons match the window's WM_CLASS (lowercase
     // "modelrouter-gui") against StartupWMClass in the .desktop file.
     backgroundColor: "#1f2937",
@@ -639,6 +649,12 @@ ipcMain.handle("shell:openPath", (_, p) => {
 // window control from renderer uses preload -> ipcMain above
 
 // ---------- bootstrap ----------
+// Defensive GPU handling: Electron's Chromium GPU process is a frequent
+// source of hard crashes (SIGSEGV) on Linux, especially on hybrid-GPU and
+// Wayland setups. The GUI host is an LLM management shell — a software
+// renderer is perfectly fine. Must run before app.whenReady.
+app.disableHardwareAcceleration();
+
 const gotLock = app.requestSingleInstanceLock();
 if (gotLock) {
   app.on("second-instance", () => {