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/worker/src/outbox_cleanup.rs

@@ -0,0 +1,31 @@
+use sqlx::PgPool;
+use std::time::Duration;
+
+pub struct OutboxCleanup {
+    pub pool: PgPool,
+    pub retention_days: i64,
+    pub interval: Duration,
+}
+
+impl OutboxCleanup {
+    pub async fn run(self) {
+        loop {
+            tokio::time::sleep(self.interval).await;
+            match self.cleanup().await {
+                Ok(n) if n > 0 => tracing::info!(deleted = n, "outbox cleanup: removed old events"),
+                Err(e) => tracing::warn!(error = %e, "outbox cleanup failed"),
+                _ => {}
+            }
+        }
+    }
+
+    async fn cleanup(&self) -> Result<u64, sqlx::Error> {
+        let result = sqlx::query(
+            "DELETE FROM outbox_events WHERE delivered = true AND delivered_at < NOW() - make_interval(days => $1)",
+        )
+        .bind(self.retention_days as i32)
+        .execute(&self.pool)
+        .await?;
+        Ok(result.rows_affected())
+    }
+}