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/postgres/src/activitypub.rs

@@ -22,7 +22,10 @@ impl PgActivityPubRepository {
 
 #[async_trait]
 impl ActivityPubRepository for PgActivityPubRepository {
-    async fn outbox_entries_for_actor(&self, user_id: &UserId) -> Result<Vec<OutboxEntry>, DomainError> {
+    async fn outbox_entries_for_actor(
+        &self,
+        user_id: &UserId,
+    ) -> Result<Vec<OutboxEntry>, DomainError> {
         #[derive(sqlx::FromRow)]
         struct Row {
             id: uuid::Uuid,
@@ -134,7 +137,10 @@ impl ActivityPubRepository for PgActivityPubRepository {
             .collect())
     }
 
-    async fn find_remote_actor_id(&self, actor_ap_url: &Url) -> Result<Option<UserId>, DomainError> {
+    async fn find_remote_actor_id(
+        &self,
+        actor_ap_url: &Url,
+    ) -> Result<Option<UserId>, DomainError> {
         sqlx::query_scalar::<_, uuid::Uuid>("SELECT id FROM users WHERE ap_id=$1")
             .bind(actor_ap_url.as_str())
             .fetch_optional(&self.pool)
@@ -148,7 +154,10 @@ impl ActivityPubRepository for PgActivityPubRepository {
             return Ok(id);
         }
         let new_id = uuid::Uuid::new_v4();
-        let handle = actor_ap_url.path().trim_start_matches('/').replace('/', "_");
+        let handle = actor_ap_url
+            .path()
+            .trim_start_matches('/')
+            .replace('/', "_");
         sqlx::query(
             "INSERT INTO users(id,username,email,password_hash,local,ap_id,created_at,updated_at)
              VALUES($1,$2,$3,'',false,$4,NOW(),NOW()) ON CONFLICT(ap_id) DO NOTHING",
@@ -163,7 +172,11 @@ impl ActivityPubRepository for PgActivityPubRepository {
         // Re-fetch to get whichever id won the race
         self.find_remote_actor_id(actor_ap_url)
             .await?
-            .ok_or_else(|| DomainError::Internal("intern_remote_actor: insert succeeded but row not found".into()))
+            .ok_or_else(|| {
+                DomainError::Internal(
+                    "intern_remote_actor: insert succeeded but row not found".into(),
+                )
+            })
     }
 
     async fn accept_note(
@@ -195,13 +208,15 @@ impl ActivityPubRepository for PgActivityPubRepository {
 
     async fn apply_note_update(&self, ap_id: &Url, new_content: &str) -> Result<(), DomainError> {
         let capped: String = new_content.chars().take(500).collect();
-        sqlx::query("UPDATE thoughts SET content=$2,updated_at=NOW() WHERE ap_id=$1 AND local=false")
-            .bind(ap_id.as_str())
-            .bind(&capped)
-            .execute(&self.pool)
-            .await
-            .map_err(|e| DomainError::Internal(e.to_string()))
-            .map(|_| ())
+        sqlx::query(
+            "UPDATE thoughts SET content=$2,updated_at=NOW() WHERE ap_id=$1 AND local=false",
+        )
+        .bind(ap_id.as_str())
+        .bind(&capped)
+        .execute(&self.pool)
+        .await
+        .map_err(|e| DomainError::Internal(e.to_string()))
+        .map(|_| ())
     }
 
     async fn retract_note(&self, ap_id: &Url) -> Result<(), DomainError> {
@@ -253,9 +268,16 @@ mod tests {
         let actor_url = url::Url::parse("https://remote.example/users/bob").unwrap();
         let ap_id = url::Url::parse("https://remote.example/notes/1").unwrap();
         let author = repo.intern_remote_actor(&actor_url).await.unwrap();
-        repo.accept_note(&ap_id, &author, "hello from remote", chrono::Utc::now(), false, None)
-            .await
-            .unwrap();
+        repo.accept_note(
+            &ap_id,
+            &author,
+            "hello from remote",
+            chrono::Utc::now(),
+            false,
+            None,
+        )
+        .await
+        .unwrap();
         repo.retract_note(&ap_id).await.unwrap();
     }