feat: implement merge readiness plan to close gaps between v2 and v1

- Task 1: Fix feed response hydration by adding `to_thought_response` helper and updating feed handlers to return full `ThoughtResponse`.
- Task 2: Wire follower/following REST routes for user feeds.
- Task 3: Add user listing and count endpoints, including `GET /users` and `GET /users/count`.
- Task 4: Implement popular tags feature with `GET /tags/popular`.
- Task 5: Enhance configuration with HOST, CORS_ORIGINS, and optional rate limiting using tower-governor.

crates/adapters/event-payload/src/lib.rs

@@ -74,20 +74,20 @@ impl EventPayload {
     /// Returns the NATS subject for this event.
     pub fn subject(&self) -> &'static str {
         match self {
-            Self::ThoughtCreated { .. }  => "thoughts.created",
-            Self::ThoughtDeleted { .. }  => "thoughts.deleted",
-            Self::ThoughtUpdated { .. }  => "thoughts.updated",
-            Self::LikeAdded { .. }       => "likes.added",
-            Self::LikeRemoved { .. }     => "likes.removed",
-            Self::BoostAdded { .. }      => "boosts.added",
-            Self::BoostRemoved { .. }    => "boosts.removed",
+            Self::ThoughtCreated { .. } => "thoughts.created",
+            Self::ThoughtDeleted { .. } => "thoughts.deleted",
+            Self::ThoughtUpdated { .. } => "thoughts.updated",
+            Self::LikeAdded { .. } => "likes.added",
+            Self::LikeRemoved { .. } => "likes.removed",
+            Self::BoostAdded { .. } => "boosts.added",
+            Self::BoostRemoved { .. } => "boosts.removed",
             Self::FollowRequested { .. } => "follows.requested",
-            Self::FollowAccepted { .. }  => "follows.accepted",
-            Self::FollowRejected { .. }  => "follows.rejected",
-            Self::Unfollowed { .. }      => "follows.removed",
-            Self::UserBlocked { .. }     => "users.blocked",
-            Self::UserUnblocked { .. }   => "users.unblocked",
-            Self::UserRegistered { .. }  => "users.registered",
+            Self::FollowAccepted { .. } => "follows.accepted",
+            Self::FollowRejected { .. } => "follows.rejected",
+            Self::Unfollowed { .. } => "follows.removed",
+            Self::UserBlocked { .. } => "users.blocked",
+            Self::UserUnblocked { .. } => "users.unblocked",
+            Self::UserRegistered { .. } => "users.registered",
         }
     }
 }
@@ -97,46 +97,102 @@ impl EventPayload {
 impl From<&DomainEvent> for EventPayload {
     fn from(e: &DomainEvent) -> Self {
         match e {
-            DomainEvent::ThoughtCreated { thought_id, user_id, in_reply_to_id } => Self::ThoughtCreated {
+            DomainEvent::ThoughtCreated {
+                thought_id,
+                user_id,
+                in_reply_to_id,
+            } => Self::ThoughtCreated {
                 thought_id: thought_id.to_string(),
                 user_id: user_id.to_string(),
                 in_reply_to_id: in_reply_to_id.as_ref().map(|x| x.to_string()),
             },
-            DomainEvent::ThoughtDeleted { thought_id, user_id } => Self::ThoughtDeleted {
-                thought_id: thought_id.to_string(), user_id: user_id.to_string(),
+            DomainEvent::ThoughtDeleted {
+                thought_id,
+                user_id,
+            } => Self::ThoughtDeleted {
+                thought_id: thought_id.to_string(),
+                user_id: user_id.to_string(),
             },
-            DomainEvent::ThoughtUpdated { thought_id, user_id } => Self::ThoughtUpdated {
-                thought_id: thought_id.to_string(), user_id: user_id.to_string(),
+            DomainEvent::ThoughtUpdated {
+                thought_id,
+                user_id,
+            } => Self::ThoughtUpdated {
+                thought_id: thought_id.to_string(),
+                user_id: user_id.to_string(),
             },
-            DomainEvent::LikeAdded { like_id, user_id, thought_id } => Self::LikeAdded {
-                like_id: like_id.to_string(), user_id: user_id.to_string(), thought_id: thought_id.to_string(),
+            DomainEvent::LikeAdded {
+                like_id,
+                user_id,
+                thought_id,
+            } => Self::LikeAdded {
+                like_id: like_id.to_string(),
+                user_id: user_id.to_string(),
+                thought_id: thought_id.to_string(),
             },
-            DomainEvent::LikeRemoved { user_id, thought_id } => Self::LikeRemoved {
-                user_id: user_id.to_string(), thought_id: thought_id.to_string(),
+            DomainEvent::LikeRemoved {
+                user_id,
+                thought_id,
+            } => Self::LikeRemoved {
+                user_id: user_id.to_string(),
+                thought_id: thought_id.to_string(),
             },
-            DomainEvent::BoostAdded { boost_id, user_id, thought_id } => Self::BoostAdded {
-                boost_id: boost_id.to_string(), user_id: user_id.to_string(), thought_id: thought_id.to_string(),
+            DomainEvent::BoostAdded {
+                boost_id,
+                user_id,
+                thought_id,
+            } => Self::BoostAdded {
+                boost_id: boost_id.to_string(),
+                user_id: user_id.to_string(),
+                thought_id: thought_id.to_string(),
             },
-            DomainEvent::BoostRemoved { user_id, thought_id } => Self::BoostRemoved {
-                user_id: user_id.to_string(), thought_id: thought_id.to_string(),
+            DomainEvent::BoostRemoved {
+                user_id,
+                thought_id,
+            } => Self::BoostRemoved {
+                user_id: user_id.to_string(),
+                thought_id: thought_id.to_string(),
             },
-            DomainEvent::FollowRequested { follower_id, following_id } => Self::FollowRequested {
-                follower_id: follower_id.to_string(), following_id: following_id.to_string(),
+            DomainEvent::FollowRequested {
+                follower_id,
+                following_id,
+            } => Self::FollowRequested {
+                follower_id: follower_id.to_string(),
+                following_id: following_id.to_string(),
             },
-            DomainEvent::FollowAccepted { follower_id, following_id } => Self::FollowAccepted {
-                follower_id: follower_id.to_string(), following_id: following_id.to_string(),
+            DomainEvent::FollowAccepted {
+                follower_id,
+                following_id,
+            } => Self::FollowAccepted {
+                follower_id: follower_id.to_string(),
+                following_id: following_id.to_string(),
             },
-            DomainEvent::FollowRejected { follower_id, following_id } => Self::FollowRejected {
-                follower_id: follower_id.to_string(), following_id: following_id.to_string(),
+            DomainEvent::FollowRejected {
+                follower_id,
+                following_id,
+            } => Self::FollowRejected {
+                follower_id: follower_id.to_string(),
+                following_id: following_id.to_string(),
             },
-            DomainEvent::Unfollowed { follower_id, following_id } => Self::Unfollowed {
-                follower_id: follower_id.to_string(), following_id: following_id.to_string(),
+            DomainEvent::Unfollowed {
+                follower_id,
+                following_id,
+            } => Self::Unfollowed {
+                follower_id: follower_id.to_string(),
+                following_id: following_id.to_string(),
             },
-            DomainEvent::UserBlocked { blocker_id, blocked_id } => Self::UserBlocked {
-                blocker_id: blocker_id.to_string(), blocked_id: blocked_id.to_string(),
+            DomainEvent::UserBlocked {
+                blocker_id,
+                blocked_id,
+            } => Self::UserBlocked {
+                blocker_id: blocker_id.to_string(),
+                blocked_id: blocked_id.to_string(),
             },
-            DomainEvent::UserUnblocked { blocker_id, blocked_id } => Self::UserUnblocked {
-                blocker_id: blocker_id.to_string(), blocked_id: blocked_id.to_string(),
+            DomainEvent::UserUnblocked {
+                blocker_id,
+                blocked_id,
+            } => Self::UserUnblocked {
+                blocker_id: blocker_id.to_string(),
+                blocked_id: blocked_id.to_string(),
             },
             DomainEvent::UserRegistered { user_id } => Self::UserRegistered {
                 user_id: user_id.to_string(),
@@ -157,60 +213,102 @@ impl TryFrom<EventPayload> for DomainEvent {
 
     fn try_from(p: EventPayload) -> Result<Self, DomainError> {
         Ok(match p {
-            EventPayload::ThoughtCreated { thought_id, user_id, in_reply_to_id } => DomainEvent::ThoughtCreated {
+            EventPayload::ThoughtCreated {
+                thought_id,
+                user_id,
+                in_reply_to_id,
+            } => DomainEvent::ThoughtCreated {
                 thought_id: ThoughtId::from_uuid(parse_uuid(&thought_id, "thought_id")?),
                 user_id: UserId::from_uuid(parse_uuid(&user_id, "user_id")?),
                 in_reply_to_id: in_reply_to_id
                     .map(|s| parse_uuid(&s, "in_reply_to_id").map(ThoughtId::from_uuid))
                     .transpose()?,
             },
-            EventPayload::ThoughtDeleted { thought_id, user_id } => DomainEvent::ThoughtDeleted {
+            EventPayload::ThoughtDeleted {
+                thought_id,
+                user_id,
+            } => DomainEvent::ThoughtDeleted {
                 thought_id: ThoughtId::from_uuid(parse_uuid(&thought_id, "thought_id")?),
                 user_id: UserId::from_uuid(parse_uuid(&user_id, "user_id")?),
             },
-            EventPayload::ThoughtUpdated { thought_id, user_id } => DomainEvent::ThoughtUpdated {
+            EventPayload::ThoughtUpdated {
+                thought_id,
+                user_id,
+            } => DomainEvent::ThoughtUpdated {
                 thought_id: ThoughtId::from_uuid(parse_uuid(&thought_id, "thought_id")?),
                 user_id: UserId::from_uuid(parse_uuid(&user_id, "user_id")?),
             },
-            EventPayload::LikeAdded { like_id, user_id, thought_id } => DomainEvent::LikeAdded {
+            EventPayload::LikeAdded {
+                like_id,
+                user_id,
+                thought_id,
+            } => DomainEvent::LikeAdded {
                 like_id: LikeId::from_uuid(parse_uuid(&like_id, "like_id")?),
                 user_id: UserId::from_uuid(parse_uuid(&user_id, "user_id")?),
                 thought_id: ThoughtId::from_uuid(parse_uuid(&thought_id, "thought_id")?),
             },
-            EventPayload::LikeRemoved { user_id, thought_id } => DomainEvent::LikeRemoved {
+            EventPayload::LikeRemoved {
+                user_id,
+                thought_id,
+            } => DomainEvent::LikeRemoved {
                 user_id: UserId::from_uuid(parse_uuid(&user_id, "user_id")?),
                 thought_id: ThoughtId::from_uuid(parse_uuid(&thought_id, "thought_id")?),
             },
-            EventPayload::BoostAdded { boost_id, user_id, thought_id } => DomainEvent::BoostAdded {
+            EventPayload::BoostAdded {
+                boost_id,
+                user_id,
+                thought_id,
+            } => DomainEvent::BoostAdded {
                 boost_id: BoostId::from_uuid(parse_uuid(&boost_id, "boost_id")?),
                 user_id: UserId::from_uuid(parse_uuid(&user_id, "user_id")?),
                 thought_id: ThoughtId::from_uuid(parse_uuid(&thought_id, "thought_id")?),
             },
-            EventPayload::BoostRemoved { user_id, thought_id } => DomainEvent::BoostRemoved {
+            EventPayload::BoostRemoved {
+                user_id,
+                thought_id,
+            } => DomainEvent::BoostRemoved {
                 user_id: UserId::from_uuid(parse_uuid(&user_id, "user_id")?),
                 thought_id: ThoughtId::from_uuid(parse_uuid(&thought_id, "thought_id")?),
             },
-            EventPayload::FollowRequested { follower_id, following_id } => DomainEvent::FollowRequested {
+            EventPayload::FollowRequested {
+                follower_id,
+                following_id,
+            } => DomainEvent::FollowRequested {
                 follower_id: UserId::from_uuid(parse_uuid(&follower_id, "follower_id")?),
                 following_id: UserId::from_uuid(parse_uuid(&following_id, "following_id")?),
             },
-            EventPayload::FollowAccepted { follower_id, following_id } => DomainEvent::FollowAccepted {
+            EventPayload::FollowAccepted {
+                follower_id,
+                following_id,
+            } => DomainEvent::FollowAccepted {
                 follower_id: UserId::from_uuid(parse_uuid(&follower_id, "follower_id")?),
                 following_id: UserId::from_uuid(parse_uuid(&following_id, "following_id")?),
             },
-            EventPayload::FollowRejected { follower_id, following_id } => DomainEvent::FollowRejected {
+            EventPayload::FollowRejected {
+                follower_id,
+                following_id,
+            } => DomainEvent::FollowRejected {
                 follower_id: UserId::from_uuid(parse_uuid(&follower_id, "follower_id")?),
                 following_id: UserId::from_uuid(parse_uuid(&following_id, "following_id")?),
             },
-            EventPayload::Unfollowed { follower_id, following_id } => DomainEvent::Unfollowed {
+            EventPayload::Unfollowed {
+                follower_id,
+                following_id,
+            } => DomainEvent::Unfollowed {
                 follower_id: UserId::from_uuid(parse_uuid(&follower_id, "follower_id")?),
                 following_id: UserId::from_uuid(parse_uuid(&following_id, "following_id")?),
             },
-            EventPayload::UserBlocked { blocker_id, blocked_id } => DomainEvent::UserBlocked {
+            EventPayload::UserBlocked {
+                blocker_id,
+                blocked_id,
+            } => DomainEvent::UserBlocked {
                 blocker_id: UserId::from_uuid(parse_uuid(&blocker_id, "blocker_id")?),
                 blocked_id: UserId::from_uuid(parse_uuid(&blocked_id, "blocked_id")?),
             },
-            EventPayload::UserUnblocked { blocker_id, blocked_id } => DomainEvent::UserUnblocked {
+            EventPayload::UserUnblocked {
+                blocker_id,
+                blocked_id,
+            } => DomainEvent::UserUnblocked {
                 blocker_id: UserId::from_uuid(parse_uuid(&blocker_id, "blocker_id")?),
                 blocked_id: UserId::from_uuid(parse_uuid(&blocked_id, "blocked_id")?),
             },
@@ -240,22 +338,65 @@ mod tests {
     #[test]
     fn all_subjects_are_unique() {
         let samples: &[EventPayload] = &[
-            EventPayload::ThoughtCreated { thought_id: "a".into(), user_id: "b".into(), in_reply_to_id: None },
-            EventPayload::ThoughtDeleted { thought_id: "a".into(), user_id: "b".into() },
-            EventPayload::ThoughtUpdated { thought_id: "a".into(), user_id: "b".into() },
-            EventPayload::LikeAdded { like_id: "a".into(), user_id: "b".into(), thought_id: "c".into() },
-            EventPayload::LikeRemoved { user_id: "b".into(), thought_id: "c".into() },
-            EventPayload::BoostAdded { boost_id: "a".into(), user_id: "b".into(), thought_id: "c".into() },
-            EventPayload::BoostRemoved { user_id: "b".into(), thought_id: "c".into() },
-            EventPayload::FollowRequested { follower_id: "a".into(), following_id: "b".into() },
-            EventPayload::FollowAccepted { follower_id: "a".into(), following_id: "b".into() },
-            EventPayload::FollowRejected { follower_id: "a".into(), following_id: "b".into() },
-            EventPayload::Unfollowed { follower_id: "a".into(), following_id: "b".into() },
-            EventPayload::UserBlocked { blocker_id: "a".into(), blocked_id: "b".into() },
+            EventPayload::ThoughtCreated {
+                thought_id: "a".into(),
+                user_id: "b".into(),
+                in_reply_to_id: None,
+            },
+            EventPayload::ThoughtDeleted {
+                thought_id: "a".into(),
+                user_id: "b".into(),
+            },
+            EventPayload::ThoughtUpdated {
+                thought_id: "a".into(),
+                user_id: "b".into(),
+            },
+            EventPayload::LikeAdded {
+                like_id: "a".into(),
+                user_id: "b".into(),
+                thought_id: "c".into(),
+            },
+            EventPayload::LikeRemoved {
+                user_id: "b".into(),
+                thought_id: "c".into(),
+            },
+            EventPayload::BoostAdded {
+                boost_id: "a".into(),
+                user_id: "b".into(),
+                thought_id: "c".into(),
+            },
+            EventPayload::BoostRemoved {
+                user_id: "b".into(),
+                thought_id: "c".into(),
+            },
+            EventPayload::FollowRequested {
+                follower_id: "a".into(),
+                following_id: "b".into(),
+            },
+            EventPayload::FollowAccepted {
+                follower_id: "a".into(),
+                following_id: "b".into(),
+            },
+            EventPayload::FollowRejected {
+                follower_id: "a".into(),
+                following_id: "b".into(),
+            },
+            EventPayload::Unfollowed {
+                follower_id: "a".into(),
+                following_id: "b".into(),
+            },
+            EventPayload::UserBlocked {
+                blocker_id: "a".into(),
+                blocked_id: "b".into(),
+            },
         ];
         let mut subjects: Vec<&str> = samples.iter().map(|p| p.subject()).collect();
         subjects.sort();
         subjects.dedup();
-        assert_eq!(subjects.len(), samples.len(), "each event must have a unique subject");
+        assert_eq!(
+            subjects.len(),
+            samples.len(),
+            "each event must have a unique subject"
+        );
     }
 }