fix(release): unbreak packaging workflow on all three platforms

- Bump electron-builder to 26.16.1 so macOS signing passes the temp keychain
  password to set-key-partition-list (upstream #10066), which the macOS 26
  runner image now enforces
- Stat asar entries with their native path in the package audit; splitting on
  path.sep made every nested file look missing on Windows
- Run the package smoke with --no-sandbox on Linux runners without a setuid
  chrome-sandbox
- Load the packaged stats dashboard over loopback HTTP in the smoke, matching
  how the app serves it since #263, and ignore Chromium's cache-only font probe

scripts/run-package-smoke.mjs

@@ -14,7 +14,12 @@ delete env.ELECTRON_RUN_AS_NODE;
 try {
   const result = spawnSync(
     require('electron'),
-    [fileURLToPath(new URL('./smoke-package.cjs', import.meta.url)), path.resolve(resources)],
+    [
+      fileURLToPath(new URL('./smoke-package.cjs', import.meta.url)),
+      path.resolve(resources),
+      // CI runners lack a setuid chrome-sandbox; this harness never loads remote content.
+      ...(process.platform === 'linux' ? ['--no-sandbox'] : []),
+    ],
     { env, stdio: 'inherit', timeout: 75_000 },
   );
   if (result.error) throw result.error;