feat: implement unread notification count and enhance user listing with pagination

crates/domain/src/models/thought.rs

@@ -25,6 +25,17 @@ pub struct Thought {
     pub updated_at: Option<DateTime<Utc>>,
 }
 
+impl Visibility {
+    pub fn as_str(&self) -> &'static str {
+        match self {
+            Visibility::Public => "public",
+            Visibility::Followers => "followers",
+            Visibility::Unlisted => "unlisted",
+            Visibility::Direct => "direct",
+        }
+    }
+}
+
 impl Thought {
     pub fn new_local(
         id: ThoughtId,

crates/domain/src/ports.rs

@@ -184,6 +184,7 @@ pub trait NotificationRepository: Send + Sync {
         user_id: &UserId,
         page: &PageParams,
     ) -> Result<Paginated<Notification>, DomainError>;
+    async fn count_unread(&self, user_id: &UserId) -> Result<u64, DomainError>;
     async fn mark_read(&self, id: &NotificationId, user_id: &UserId) -> Result<(), DomainError>;
     async fn mark_all_read(&self, user_id: &UserId) -> Result<(), DomainError>;
 }

crates/domain/src/testing.rs

@@ -498,6 +498,15 @@ impl NotificationRepository for TestStore {
             per_page: 20,
         })
     }
+    async fn count_unread(&self, uid: &UserId) -> Result<u64, DomainError> {
+        Ok(self
+            .notifications
+            .lock()
+            .unwrap()
+            .iter()
+            .filter(|n| &n.user_id == uid && !n.read)
+            .count() as u64)
+    }
     async fn mark_read(&self, id: &NotificationId, _uid: &UserId) -> Result<(), DomainError> {
         if let Some(n) = self
             .notifications