feat: Implement application bootstrap and window management

- Added bootstrap functionality to initialize the Electron application.
- Created a new paths module to manage application paths and URLs.
- Introduced a shutdown service to handle graceful application shutdowns.
- Refactored error logging to use a dedicated logger module.
- Implemented process killing logic for NodeCG processes across platforms.
- Established navigation policies for internal and external URL handling in windows.
- Developed window service for creating and managing application windows.
- Added tests for application paths, application controller, navigation policies, process killer, and shutdown service.

src/tests/shutdown-service.test.ts

@@ -0,0 +1,32 @@
+import assert from "node:assert/strict";
+import test from "node:test";
+
+import { createShutdownService } from "../main/app/shutdown-service";
+
+test("shutdown service reuses the same stop promise while stopping", async () => {
+  let stopCalls = 0;
+  let releaseStop: () => void = () => {
+    throw new Error("stop promise was not created");
+  };
+  const service = createShutdownService(
+    () =>
+      new Promise<void>((resolve) => {
+        stopCalls += 1;
+        releaseStop = resolve;
+      }),
+  );
+
+  const first = service.stop();
+  const second = service.stop();
+
+  assert.equal(first, second);
+  assert.equal(stopCalls, 1);
+  assert.equal(service.getState(), "stopping");
+
+  releaseStop();
+  await first;
+
+  assert.equal(service.getState(), "stopped");
+  await service.stop();
+  assert.equal(stopCalls, 1);
+});