fix(federation): fix 27 AP bugs, gaps, and inconsistencies

Round 1 — 18 bug fixes:
- remote likes/boosts now persist in engagement tables
- intern_remote_actor uses name@domain, expanded username to VARCHAR(255)
- PgRemoteActorRepository upsert/find now handles all fields
- update_following_status no longer a no-op, count_followers counts all
- accept/reject follow publishes event before DB mark (atomicity)
- fetch_outbox_page follows pagination via next links
- actor URL canonicalized to /users/{uuid}
- content_to_html escapes single quotes
- WebFinger accepts application/ld+json type
- try_from_ap accepts Article and Page object types
- feed SQL uses parameterized viewer UUID instead of format!
- content cap raised from 500 to 5000 chars
- also_known_as changed from Option<String> to Vec<String>
- connections fetch always triggers from page 1

Round 2 — 9 gap fixes:
- on_announce_removed handler deletes boost row on Undo(Announce)
- on_update handles Person/Service/Group actor profile updates
- sync_remote_actor_to_user syncs remote_actors → users on create/update
- FederationBlockPort: block_by_username sends Block activity to remote
- domain RemoteActor gains inbox_url, shared_inbox_url fields
- remote_actors attachment column (JSONB) with read/write
- .well-known/host-meta endpoint
- 256KB body limit on AP inbox routes
- outbox cleanup job (7-day retention, hourly sweep)

crates/application/src/use_cases/federation_management/tests.rs

@@ -11,10 +11,12 @@ fn remote_actor(url: &str, handle: &str) -> RemoteActor {
         avatar_url: None,
         bio: None,
         banner_url: None,
-        also_known_as: None,
+        also_known_as: vec![],
         outbox_url: None,
         followers_url: None,
         following_url: None,
+        inbox_url: None,
+        shared_inbox_url: None,
         attachment: vec![],
         last_fetched_at: Utc::now(),
     }