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/activitypub/src/note.rs

@@ -1,5 +1,5 @@
-use activitypub_base::AS_PUBLIC;
 use activitypub_base::NoteType;
+use activitypub_base::AS_PUBLIC;
 use chrono::{DateTime, Utc};
 use serde::{Deserialize, Serialize};
 use url::Url;
@@ -27,16 +27,26 @@ pub struct ThoughtNote {
 
 impl ThoughtNote {
     pub fn new_public(
-        id: Url, actor_url: Url, content: String, published: DateTime<Utc>,
-        in_reply_to: Option<Url>, sensitive: bool, summary: Option<String>,
+        id: Url,
+        actor_url: Url,
+        content: String,
+        published: DateTime<Utc>,
+        in_reply_to: Option<Url>,
+        sensitive: bool,
+        summary: Option<String>,
         followers_url: Url,
     ) -> Self {
         Self {
             kind: Default::default(),
-            id, attributed_to: actor_url, content, published,
+            id,
+            attributed_to: actor_url,
+            content,
+            published,
             to: vec![AS_PUBLIC.to_string()],
             cc: vec![followers_url.to_string()],
-            in_reply_to, sensitive, summary,
+            in_reply_to,
+            sensitive,
+            summary,
         }
     }
 }
@@ -52,7 +62,9 @@ mod tests {
             "https://example.com/users/alice".parse().unwrap(),
             "Hello world".to_string(),
             chrono::Utc::now(),
-            None, false, None,
+            None,
+            false,
+            None,
             "https://example.com/users/alice/followers".parse().unwrap(),
         );
         let json = serde_json::to_string(&note).unwrap();