feat(core): add Electron runtime, services, and app composition

src/core/services/overlay-window-config.test.ts

@@ -0,0 +1,11 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import fs from 'node:fs';
+import path from 'node:path';
+
+test('overlay window config explicitly disables renderer sandbox for preload compatibility', () => {
+  const sourcePath = path.join(process.cwd(), 'src/core/services/overlay-window.ts');
+  const source = fs.readFileSync(sourcePath, 'utf8');
+
+  assert.match(source, /webPreferences:\s*\{[\s\S]*sandbox:\s*false[\s\S]*\}/m);
+});