Fix archive project appearing to do nothing

The archive mutation lacked user feedback:
- No toast notification on success/failure
- Navigated to /projects instead of /dashboard after archiving
- No error handling if the API call failed

Added success/error toasts using the existing ToastContext, navigate
to /dashboard after archiving (matching user expectations), and error
toast on failure.

Co-Authored-By: Paperclip <noreply@paperclip.ing>
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

ui/src/pages/ProjectDetail.tsx

@@ -10,6 +10,7 @@ import { heartbeatsApi } from "../api/heartbeats";
 import { assetsApi } from "../api/assets";
 import { usePanel } from "../context/PanelContext";
 import { useCompany } from "../context/CompanyContext";
+import { useToast } from "../context/ToastContext";
 import { useBreadcrumbs } from "../context/BreadcrumbContext";
 import { queryKeys } from "../lib/queryKeys";
 import { ProjectProperties, type ProjectConfigFieldKey, type ProjectFieldSaveState } from "../components/ProjectProperties";
@@ -213,6 +214,7 @@ export function ProjectDetail() {
   const queryClient = useQueryClient();
   const navigate = useNavigate();
   const location = useLocation();
+  const { pushToast } = useToast();
   const [fieldSaveStates, setFieldSaveStates] = useState<Partial<Record<ProjectConfigFieldKey, ProjectFieldSaveState>>>({});
   const fieldSaveRequestIds = useRef<Partial<Record<ProjectConfigFieldKey, number>>>({});
   const fieldSaveTimers = useRef<Partial<Record<ProjectConfigFieldKey, ReturnType<typeof setTimeout>>>>({});
@@ -287,9 +289,18 @@ export function ProjectDetail() {
     onSuccess: (_, archived) => {
       invalidateProject();
       if (archived) {
-        navigate("/projects");
+        pushToast({ title: "Project archived", tone: "success" });
+        navigate("/dashboard");
+      } else {
+        pushToast({ title: "Project unarchived", tone: "success" });
       }
     },
+    onError: (_, archived) => {
+      pushToast({
+        title: archived ? "Failed to archive project" : "Failed to unarchive project",
+        tone: "error",
+      });
+    },
   });
 
   const uploadImage = useMutation({