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/repository/blocklist.rs

@@ -0,0 +1,35 @@
+use anyhow::Result;
+use async_trait::async_trait;
+
+use super::BlockedDomain;
+
+/// Domain and actor-level blocklists.
+#[async_trait]
+pub trait BlocklistRepository: Send + Sync {
+    // ── Domain blocklist ────────────────────────────────────────────────────
+    async fn add_blocked_domain(&self, domain: &str, reason: Option<&str>) -> Result<()>;
+    async fn remove_blocked_domain(&self, domain: &str) -> Result<()>;
+    async fn get_blocked_domains(&self) -> Result<Vec<BlockedDomain>>;
+    async fn is_domain_blocked(&self, domain: &str) -> Result<bool>;
+
+    // ── Per-user actor blocklist ────────────────────────────────────────────
+    async fn add_blocked_actor(
+        &self,
+        local_user_id: uuid::Uuid,
+        actor_url: &str,
+    ) -> Result<()>;
+    async fn remove_blocked_actor(
+        &self,
+        local_user_id: uuid::Uuid,
+        actor_url: &str,
+    ) -> Result<()>;
+    async fn get_blocked_actors(
+        &self,
+        local_user_id: uuid::Uuid,
+    ) -> Result<Vec<String>>;
+    async fn is_actor_blocked(
+        &self,
+        local_user_id: uuid::Uuid,
+        actor_url: &str,
+    ) -> Result<bool>;
+}