refactor: wrap direct port calls behind use cases — notifications, search, popular_tags

crates/application/src/use_cases/feed.rs

@@ -4,7 +4,7 @@ use domain::{
         feed::{FeedEntry, PageParams, Paginated, UserSummary},
         user::User,
     },
-    ports::{FeedRepository, FollowRepository, UserRepository},
+    ports::{FeedRepository, FollowRepository, TagRepository, UserRepository},
     value_objects::UserId,
 };
 
@@ -40,3 +40,7 @@ pub async fn search(feed: &dyn FeedRepository, query: &str, page: PageParams, vi
 pub async fn list_users(users: &dyn UserRepository) -> Result<Vec<UserSummary>, DomainError> {
     users.list_with_stats().await
 }
+
+pub async fn get_popular_tags(tags: &dyn TagRepository, limit: usize) -> Result<Vec<(String, i64)>, DomainError> {
+    tags.popular_tags(limit).await
+}