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)

thoughts-frontend/components/remote-user-profile/profile-card.tsx

@@ -58,17 +58,22 @@ export function ProfileCard({ actor, action }: ProfileCardProps) {
         </Link>
       </Button>
 
-      {actor.alsoKnownAs && (
+      {actor.alsoKnownAs.length > 0 && (
         <p className="mt-2 text-xs text-muted-foreground">
           Also known as:{" "}
-          <Link
-            href={actor.alsoKnownAs}
-            target="_blank"
-            rel="noopener noreferrer"
-            className="underline"
-          >
-            {actor.alsoKnownAs}
-          </Link>
+          {actor.alsoKnownAs.map((aka, i) => (
+            <span key={aka}>
+              {i > 0 && ", "}
+              <Link
+                href={aka}
+                target="_blank"
+                rel="noopener noreferrer"
+                className="underline"
+              >
+                {aka}
+              </Link>
+            </span>
+          ))}
         </p>
       )}