Fix file retention after updates on macOS #417

This fixes issue #417 where autoupdate installer files were not deleted
on macOS, leading to accumulation of old installers.

Key changes:

- Store update files in application-specific directory
- Clear update files directory on every app launch

Other supporting changes:

- Refactor file system operations to be more testable and reusable
- Improve separation of concerns in directory management
- Enhance dependency injection for auto-update logic
- Fix async completion to support `await` operations
- Add additional logging and revise some log messages during updates

tests/unit/shared/Stubs/ApplicationDirectoryProviderStub.ts

@@ -0,0 +1,41 @@
+import type {
+  DirectoryCreationOutcome,
+  ApplicationDirectoryProvider,
+  DirectoryType,
+  DirectoryCreationError,
+} from '@/infrastructure/FileSystem/Directory/ApplicationDirectoryProvider';
+
+export class ApplicationDirectoryProviderStub implements ApplicationDirectoryProvider {
+  private directoryPaths: Record<DirectoryType, string> = {
+    'update-installation-files': `[${ApplicationDirectoryProviderStub.name}]update installation files directory`,
+    'script-runs': `[${ApplicationDirectoryProviderStub.name}]scripts directory`,
+  };
+
+  private failure: DirectoryCreationError | undefined = undefined;
+
+  public withDirectoryPath(type: DirectoryType, directoryPath: string): this {
+    this.directoryPaths[type] = directoryPath;
+    return this;
+  }
+
+  public provideDirectory(type: DirectoryType): Promise<DirectoryCreationOutcome> {
+    if (this.failure) {
+      return Promise.resolve({
+        success: false,
+        error: this.failure,
+      });
+    }
+    return Promise.resolve({
+      success: true,
+      directoryAbsolutePath: this.directoryPaths[type],
+    });
+  }
+
+  public withFailure(error?: DirectoryCreationError): this {
+    this.failure = error ?? {
+      type: 'DirectoryWriteError',
+      message: `[${ApplicationDirectoryProviderStub.name}]injected failure`,
+    };
+    return this;
+  }
+}