Package game as Electron desktop app

Custom app:// privileged protocol (standard, secure, fetch, stream) serves
the game so absolute /assets/ fetches and streamed mp3 loops work without
game code changes. Borderless windowed fullscreen, F11/F12/Ctrl+R/Ctrl+Shift+I
accelerators, single-instance lock, and an opt-in MS_VERIFY harness that
drives a run and dumps asset/audio diagnostics.

Pinned electron@40.10.2 + electron-builder@25.1.8 for Node 20 compatibility.
Builder allowlist ships only runtime content and excludes assets/raw.

.gitignore

@@ -1,6 +1,8 @@
 tools/.env
 tools/.venv/
 assets/raw/
+node_modules/
+dist/
 .playwright-mcp/
 .serena/
 served-state.txt

desktop/main.js

@@ -0,0 +1,134 @@
+// ---- MeatSlicer desktop shell (Electron main process) ----
+// Serves the game over a privileged app:// scheme so the renderer keeps a real
+// origin: fetch() in js/sfxbank.js uses absolute /assets/... paths, and 28 mp3
+// tracks stream through <audio> elements. Both need standard+stream privileges.
+const { app, BrowserWindow, Menu, net, protocol } = require('electron');
+const path = require('node:path');
+const fs = require('node:fs');
+const { pathToFileURL } = require('node:url');
+
+const GAME_ROOT = path.join(__dirname, '..');
+
+protocol.registerSchemesAsPrivileged([
+  {
+    scheme: 'app',
+    privileges: { standard: true, secure: true, supportFetchAPI: true, stream: true },
+  },
+]);
+
+const gotLock = app.requestSingleInstanceLock();
+if (!gotLock) app.quit();
+
+app.setName('MeatSlicer');
+
+// Mirrors the allowlisting in tools/serve_game.py: URL path -> file under the
+// game root, with traversal protection. decodeURIComponent is required because
+// the music loader encodes spaces ("Blood%20Arcade.mp3"), and path.join (not
+// resolve) because pathname always begins with "/".
+function installProtocol() {
+  protocol.handle('app', (req) => {
+    const { pathname } = new URL(req.url);
+    let rel;
+    try { rel = decodeURIComponent(pathname); } catch (e) { rel = pathname; }
+    if (rel === '/' || rel === '') rel = '/index.html';
+    const served = path.normalize(path.join(GAME_ROOT, rel));
+    if (served !== GAME_ROOT && !served.startsWith(GAME_ROOT + path.sep)) {
+      return new Response('forbidden', { status: 400 });
+    }
+    return net.fetch(pathToFileURL(served).toString());
+  });
+}
+
+function createWindow() {
+  const win = new BrowserWindow({
+    fullscreen: true,           // borderless windowed fullscreen on Windows
+    width: 1280, height: 832,   // restore-down geometry when F11 exits
+    backgroundColor: '#040305', // matches css/style.css body
+    show: false,
+    autoHideMenuBar: true,
+  });
+  Menu.setApplicationMenu(null);
+  win.once('ready-to-show', () => win.show());
+
+  // Menu removal also removes the default F11/DevTools/reload accelerators.
+  // F12 and Ctrl+Shift+I are kept for debugging; Escape stays bound to pause
+  // inside the game, so fullscreen is F11-only.
+  win.webContents.on('before-input-event', (event, input) => {
+    if (input.type !== 'keyDown') return;
+    const key = (input.key || '').toLowerCase();
+    if (input.key === 'F11') {
+      win.setFullScreen(!win.isFullScreen());
+      event.preventDefault();
+    } else if (input.key === 'F12' || (key === 'i' && input.control && input.shift)) {
+      win.webContents.toggleDevTools();
+      event.preventDefault();
+    } else if (key === 'r' && input.control && !input.shift && !input.alt) {
+      win.webContents.reload();
+      event.preventDefault();
+    }
+  });
+
+  installVerifyHarness(win);
+  win.loadURL('app://meatslicer/index.html');
+}
+
+// Optional headless verification: set MS_VERIFY_OUT (json path) and optionally
+// MS_VERIFY_SHOT (png path). Drives a run, drains the SFX bank, captures the
+// level-up draft, writes results, and quits. Used to prove the packaged build
+// serves every asset through the custom protocol.
+function installVerifyHarness(win) {
+  const outJson = process.env.MS_VERIFY_OUT;
+  if (!outJson) return;
+  const outPng = process.env.MS_VERIFY_SHOT;
+  const log = [];
+  win.webContents.on('console-message', (event, level, message) => {
+    // Older Electron passes (event, level, message, line, sourceId); newer
+    // versions pass a single params object carrying the same fields.
+    const p = (event && typeof event === 'object' && 'message' in event) ? event : { level, message };
+    if (p.level >= 2) log.push((p.level === 3 ? 'ERROR ' : 'WARN ') + p.message);
+  });
+  win.webContents.on('did-finish-load', () => {
+    (async () => {
+      try {
+        await win.webContents.executeJavaScript('startRun(); 0');
+        const waitFor = async (expr, timeoutMs) => {
+          const deadline = Date.now() + timeoutMs;
+          while (Date.now() < deadline) {
+            if (await win.webContents.executeJavaScript(expr)) return true;
+            await new Promise(r => setTimeout(r, 250));
+          }
+          return false;
+        };
+        const spritesReady = await waitFor('!!G.imagesLoaded && G.mode === "play"', 30000);
+        const sfxReady = await waitFor('SfxBank.pending.size === 0', 30000);
+        await win.webContents.executeJavaScript(
+          "G.perkChoices = ['critbone','ember','spiteflesh'].map(id => PERKS.find(p => p.id === id)); G.mode = 'levelup'; 0"
+        );
+        await new Promise(r => setTimeout(r, 500));
+        if (outPng) fs.writeFileSync(outPng, (await win.webContents.capturePage()).toPNG());
+        const info = await win.webContents.executeJavaScript(`({
+          imagesLoaded: G.imagesLoaded,
+          mode: G.mode,
+          sfxBuffers: SfxBank.buffers.size,
+          sfxFailed: SfxBank.failed.size,
+          perkIcon: !!Sprites.imgs['perk_critbone'],
+          itemIcon: !!Sprites.imgs['i_rerollrib'],
+          music: Music.current ? Music.current.name : null,
+        })`);
+        fs.writeFileSync(outJson, JSON.stringify({ spritesReady, sfxReady, info, log }, null, 2));
+      } catch (err) {
+        fs.writeFileSync(outJson, JSON.stringify({ error: String((err && err.stack) || err), log }, null, 2));
+      } finally {
+        app.quit();
+      }
+    })();
+  });
+}
+
+app.whenReady().then(() => {
+  installProtocol();
+  createWindow();
+  app.on('activate', () => { if (BrowserWindow.getAllWindows().length === 0) createWindow(); });
+});
+
+app.on('window-all-closed', () => { if (process.platform !== 'darwin') app.quit(); });

electron-builder.yml

@@ -0,0 +1,16 @@
+appId: com.meatslicer.game
+productName: MeatSlicer
+asar: false
+files:
+  - "desktop/**"
+  - "index.html"
+  - "css/**"
+  - "js/**"
+  - "assets/**"
+  - "!assets/raw/**"
+  - "mp3-music/**"
+  - "package.json"
+win:
+  target:
+    - zip
+  icon: build/icon.png

package.json

@@ -0,0 +1,17 @@
+{
+  "name": "meatslicer",
+  "productName": "MeatSlicer",
+  "version": "0.1.0",
+  "private": true,
+  "description": "A Butcher's Descent - clear, harvest, descend.",
+  "main": "desktop/main.js",
+  "scripts": {
+    "start": "electron .",
+    "dist": "electron-builder --win zip",
+    "test": "node test/smoke.js"
+  },
+  "devDependencies": {
+    "electron": "^40.10.2",
+    "electron-builder": "^25.1.8"
+  }
+}