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/auth/src/lib.rs

@@ -1,12 +1,12 @@
 use async_trait::async_trait;
 use chrono::{Duration, Utc};
-use jsonwebtoken::{decode, encode, DecodingKey, EncodingKey, Header, Validation};
-use serde::{Deserialize, Serialize};
 use domain::{
     errors::DomainError,
     ports::{AuthService, GeneratedToken, PasswordHasher},
     value_objects::{PasswordHash, UserId},
 };
+use jsonwebtoken::{decode, encode, DecodingKey, EncodingKey, Header, Validation};
+use serde::{Deserialize, Serialize};
 
 #[derive(Serialize, Deserialize)]
 struct Claims {
@@ -21,7 +21,10 @@ pub struct JwtAuthService {
 
 impl JwtAuthService {
     pub fn new(secret: String, ttl_seconds: i64) -> Self {
-        Self { secret, ttl_seconds }
+        Self {
+            secret,
+            ttl_seconds,
+        }
     }
 }
 
@@ -51,8 +54,8 @@ impl AuthService for JwtAuthService {
             &Validation::default(),
         )
         .map_err(|_| DomainError::Unauthorized)?;
-        let uuid = uuid::Uuid::parse_str(&data.claims.sub)
-            .map_err(|_| DomainError::Unauthorized)?;
+        let uuid =
+            uuid::Uuid::parse_str(&data.claims.sub).map_err(|_| DomainError::Unauthorized)?;
         Ok(UserId::from_uuid(uuid))
     }
 }
@@ -62,10 +65,7 @@ pub struct Argon2PasswordHasher;
 #[async_trait]
 impl PasswordHasher for Argon2PasswordHasher {
     async fn hash(&self, plain: &str) -> Result<PasswordHash, DomainError> {
-        use argon2::{
-            password_hash::SaltString,
-            Argon2, PasswordHasher as _,
-        };
+        use argon2::{password_hash::SaltString, Argon2, PasswordHasher as _};
         use rand::rngs::OsRng;
         let salt = SaltString::generate(OsRng);
         let hash = Argon2::default()
@@ -77,8 +77,7 @@ impl PasswordHasher for Argon2PasswordHasher {
 
     async fn verify(&self, plain: &str, hash: &PasswordHash) -> Result<bool, DomainError> {
         use argon2::{password_hash::PasswordHash as ArgonHash, Argon2, PasswordVerifier};
-        let parsed = ArgonHash::new(&hash.0)
-            .map_err(|e| DomainError::Internal(e.to_string()))?;
+        let parsed = ArgonHash::new(&hash.0).map_err(|e| DomainError::Internal(e.to_string()))?;
         Ok(Argon2::default()
             .verify_password(plain.as_bytes(), &parsed)
             .is_ok())