fix(federation): resolve code review issues in upload size mismatch

- Fix critical: outbox worker now copies file_rejected payload fields
  (attachmentId, sourceFilename, rejectionReason, rejectionLimit,
  affectedUserIds) so the reverse relay actually delivers them
- Fix: add sourceFilename to file_rejected event for reliable
  multi-attachment matching on the sender side
- Fix: change text-accent-warning to text-accent-amber (valid class)
- Add Array.isArray guard on federationMeta parse

packages/web/src/components/chat/AttachmentRenderer.tsx

@@ -70,7 +70,7 @@ export function AttachmentRenderer({ attachment }: AttachmentRendererProps) {
       }
       return (
         <Tooltip content={tooltipText} position="top">
-          <div className="absolute top-2 right-2 flex items-center gap-1 px-1.5 py-0.5 rounded glass-pill text-xs text-accent-warning">
+          <div className="absolute top-2 right-2 flex items-center gap-1 px-1.5 py-0.5 rounded glass-pill text-xs text-accent-amber">
             <svg className="w-3 h-3" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2" strokeLinecap="round" strokeLinejoin="round">
               <path d="M10.29 3.86 1.82 18a2 2 0 0 0 1.71 3h16.94a2 2 0 0 0 1.71-3L13.71 3.86a2 2 0 0 0-3.42 0z" />
               <line x1="12" y1="9" x2="12" y2="13" />