feat(jobs): Implement garbage collection job

@@ -93,6 +93,11 @@ class JobsContent extends StatelessWidget {
                   );
                 },
               ),
+              const SizedBox(height: 10),

@@ -95,1 +95,4 @@
               ),
+              const SizedBox(height: 10),
+              BrandButton.text(
+                onPressed: () => context.read<JobsCubit>().collectNixGarbage(),

@@ -65,0 +74,4 @@
+      !jobs.any((final job) => job is CollectNixGarbageJob);
+
+  @override
+  Future<(bool, String)> execute() async => (false, 'unimplemented');