refactor!: CQRS repository split — v0.3.0

FederationRepository (34 methods) → 4 focused traits:
  ActivityRepository  (2)  — idempotency tracking
  FollowRepository    (18) — follower/following graph + migration
  ActorRepository     (6)  — keypairs, remote actor cache, announce tracking
  BlocklistRepository (8)  — domain + actor blocklists

ApObjectHandler (10 methods) → 2 traits:
  ApContentReader  (3) — get_local_objects_for_user/page, count_local_posts
  ApObjectHandler  (9) — all inbox callbacks (on_create, on_mention, etc.)

Builder changes from positional args to named setters:
  ActivityPubService::builder(base_url)
    .activity_repo(arc)
    .follow_repo(arc)
    .actor_repo(arc)
    .blocklist_repo(arc)
    .user_repo(arc)
    .content_reader(arc)
    .object_handler(arc)
    .build()

No behaviour changes.

src/activities/helpers.rs

@@ -9,13 +9,13 @@ use crate::error::Error;
 /// On repo error, skips the check rather than silently dropping the activity.
 pub(crate) async fn already_processed(activity_id: &Url, data: &Data<FederationData>) -> bool {
     let id = activity_id.as_str();
-    match data.federation_repo.is_activity_processed(id).await {
+    match data.activity_repo.is_activity_processed(id).await {
         Ok(true) => {
             tracing::debug!(activity_id = id, "duplicate activity, skipping");
             true
         }
         Ok(false) => {
-            if let Err(e) = data.federation_repo.mark_activity_processed(id).await {
+            if let Err(e) = data.activity_repo.mark_activity_processed(id).await {
                 tracing::warn!(activity_id = id, error = %e, "failed to mark activity processed");
             }
             false
@@ -39,7 +39,7 @@ pub(crate) async fn check_guards(
         return Ok(true);
     }
     let domain = actor.host_str().unwrap_or("");
-    if data.federation_repo.is_domain_blocked(domain).await? {
+    if data.blocklist_repo.is_domain_blocked(domain).await? {
         tracing::info!(actor = %actor, "ignoring activity from blocked domain");
         return Ok(true);
     }