feat: move mark-as-read logic from navigation to view loading

- Remove mark-as-read logic from NewActivityView navigation handlers
- Add mark-as-read logic to RecentOffersToUserView and RecentOffersToUserProjectsView after data loading
- Improve "You've already seen all the following" marker positioning
- Update marker styling with dashed border and centered text

This ensures the marker appears at the correct position in the list
instead of always at the top, providing better UX when viewing offers.

src/views/NewActivityView.vue

@@ -322,12 +322,10 @@ export default class NewActivityView extends Vue {
   }
 
   async handleSeeAllOffersToUser() {
-    await this.expandOffersToUserAndMarkRead(true);
     this.$router.push("/recent-offers-to-user");
   }
 
   async handleSeeAllOffersToUserProjects() {
-    await this.expandOffersToUserProjectsAndMarkRead(true);
     this.$router.push("/recent-offers-to-user-projects");
   }
 }