Refactor database error handling across repositories to use IntoDbResult for improved error management

- Updated PgNotificationRepository to utilize IntoDbResult for error handling in various methods.
- Refactored PgRemoteActorRepository to replace manual error mapping with IntoDbResult.
- Modified PgRemoteActorConnectionRepository to implement IntoDbResult for error handling.
- Adjusted PgTagRepository to use IntoDbResult for consistent error management.
- Introduced test_helpers module for seeding users and thoughts in tests.
- Enhanced PgThoughtRepository to leverage IntoDbResult for error handling.
- Updated PgTopFriendRepository to utilize IntoDbResult for error management.
- Refactored PgUserRepository to implement IntoDbResult for error handling.
- Added constants for pagination defaults in requests.
- Introduced MAX_TOP_FRIENDS constant for top friends validation.
- Refactored JWT expiration time to use a constant.
- Improved rate limiter configuration with constants for better readability.
- Added utility methods for FollowState and Visibility enums for string conversions.
- Introduced maximum length constants for Username, Email, and Content value objects.
- Cleaned up test modules by removing redundant code and utilizing a shared testing state.

crates/adapters/postgres/src/test_helpers.rs

@@ -0,0 +1,37 @@
+use crate::{thought::PgThoughtRepository, user::PgUserRepository};
+use domain::{
+    models::{
+        thought::{Thought, Visibility},
+        user::User,
+    },
+    ports::{ThoughtRepository, UserRepository},
+    value_objects::{Content, Email, PasswordHash, ThoughtId, UserId, Username},
+};
+
+pub async fn seed_user(pool: &sqlx::PgPool, username: &str, email: &str) -> User {
+    let repo = PgUserRepository::new(pool.clone());
+    let u = User::new_local(
+        UserId::new(),
+        Username::new(username).unwrap(),
+        Email::new(email).unwrap(),
+        PasswordHash("h".into()),
+    );
+    repo.save(&u).await.unwrap();
+    u
+}
+
+pub async fn seed_user_and_thought(pool: &sqlx::PgPool) -> (User, Thought) {
+    let user = seed_user(pool, "alice", "alice@ex.com").await;
+    let trepo = PgThoughtRepository::new(pool.clone());
+    let t = Thought::new_local(
+        ThoughtId::new(),
+        user.id.clone(),
+        Content::new_local("hi").unwrap(),
+        None,
+        Visibility::Public,
+        None,
+        false,
+    );
+    trepo.save(&t).await.unwrap();
+    (user, t)
+}