diff --git a/electron/package.json b/electron/package.json
index afac7c5ccc..423e639bc0 100644
--- a/electron/package.json
+++ b/electron/package.json
@@ -51,6 +51,7 @@
     "files": [
       "main.js",
       "preload.js",
+      "loginManager.js",
       "sqlite-inspection.js",
       "package.json",
       "node_modules/**/*"
diff --git a/tests/unit/electron-main.test.ts b/tests/unit/electron-main.test.ts
index eb50c65680..8ccacc7ddd 100644
--- a/tests/unit/electron-main.test.ts
+++ b/tests/unit/electron-main.test.ts
@@ -13,7 +13,7 @@
 
 import { describe, it } from "node:test";
 import assert from "node:assert/strict";
-import { mkdtempSync, rmSync } from "node:fs";
+import { mkdtempSync, rmSync, readFileSync } from "node:fs";
 import { tmpdir } from "node:os";
 import { join } from "node:path";
 import { createRequire } from "node:module";
@@ -38,6 +38,44 @@ function raceDelays(firstMs, secondMs) {
   });
 }
 
+// ─── Packaging manifest completeness (#3292 regression) ──────
+//
+// The packaged Electron app (electron-builder asar) only ships the files
+// listed in `build.files`. When #3292 added `electron/loginManager.js` and a
+// `require("./loginManager")` in main.js without adding it to `build.files`,
+// the packaged app crashed at startup with "Cannot find module './loginManager'"
+// — caught only by the CI smoke test on Linux/macOS. This guard asserts that
+// every local `require("./x")` in the Electron entry points is shipped.
+
+describe("Electron packaging manifest completeness (#3292)", () => {
+  const electronDir = join(import.meta.dirname, "../../electron");
+  const pkg = JSON.parse(readFileSync(join(electronDir, "package.json"), "utf8"));
+  const files: string[] = pkg.build?.files ?? [];
+
+  function localRequires(entry: string): string[] {
+    const src = readFileSync(join(electronDir, entry), "utf8");
+    const out = new Set<string>();
+    for (const m of src.matchAll(/require\(["'](\.\/[A-Za-z0-9_./-]+)["']\)/g)) {
+      // normalize "./loginManager" -> "loginManager.js" (entry points require sibling .js)
+      let rel = m[1].replace(/^\.\//, "");
+      if (!/\.[a-z]+$/.test(rel)) rel += ".js";
+      out.add(rel);
+    }
+    return [...out];
+  }
+
+  for (const entry of ["main.js", "preload.js"]) {
+    it(`ships every local require() of ${entry} in build.files`, () => {
+      for (const dep of localRequires(entry)) {
+        assert.ok(
+          files.includes(dep),
+          `electron/${dep} is require()d by ${entry} but missing from package.json build.files — the packaged app will crash with "Cannot find module"`
+        );
+      }
+    });
+  }
+});
+
 // ─── URL Validation Tests ────────────────────────────────────
 
 describe("Electron URL Validation", () => {