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/main/app/shutdown-service.ts

@@ -0,0 +1,32 @@
+export type AppShutdownState = "running" | "stopping" | "stopped";
+
+export type ShutdownService = {
+  getState: () => AppShutdownState;
+  stop: () => Promise<void>;
+};
+
+export function createShutdownService(stopRuntime: () => Promise<void>): ShutdownService {
+  let state: AppShutdownState = "running";
+  let stopPromise: Promise<void> | null = null;
+
+  return {
+    getState: () => state,
+    stop: () => {
+      if (state === "stopped") {
+        return Promise.resolve();
+      }
+
+      if (stopPromise) {
+        return stopPromise;
+      }
+
+      state = "stopping";
+      stopPromise = stopRuntime().finally(() => {
+        state = "stopped";
+        stopPromise = null;
+      });
+
+      return stopPromise;
+    },
+  };
+}