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/server/src/routes/federation.ts

@@ -2312,14 +2312,13 @@ function processFileRejectedEvent(
     .where(eq(schema.attachments.dmMessageId, localMsg.id))
     .all();
 
-  // The attachmentId from the remote is their local attachment ID, not ours.
-  // Match by sourceUrl instead — the remote's sourceUrl points to our upload endpoint.
-  const ourOrigin = getOurOrigin();
-  let matchedAttachment = messageAttachments.find(a =>
-    a.sourceUrl && a.sourceUrl.startsWith(ourOrigin),
-  );
+  // Match by filename from the sourceUrl — the remote sends the filename portion
+  // (e.g., "12345.png") which matches our local attachment's filename.
+  let matchedAttachment = event.sourceFilename
+    ? messageAttachments.find(a => a.filename === event.sourceFilename)
+    : undefined;
 
-  // If only one attachment, use it directly
+  // Fallback: if only one attachment, use it directly
   if (!matchedAttachment && messageAttachments.length === 1) {
     matchedAttachment = messageAttachments[0];
   }
@@ -2357,7 +2356,8 @@ function processFileRejectedEvent(
   let existingMeta: Array<{ userId: string; username: string; limit: number }> = [];
   if (matchedAttachment.federationMeta) {
     try {
-      existingMeta = JSON.parse(matchedAttachment.federationMeta);
+      const parsed = JSON.parse(matchedAttachment.federationMeta);
+      existingMeta = Array.isArray(parsed) ? parsed : [];
     } catch { /* ignore parse errors */ }
   }
 

packages/server/src/utils/federationWorker.ts

@@ -179,6 +179,12 @@ async function processOutboxTick(): Promise<void> {
       if (parsed.ownership) evt.ownership = parsed.ownership;
       if (parsed.group) evt.group = parsed.group;
       if (parsed.friendship) evt.friendship = parsed.friendship;
+      // file_rejected event fields
+      if (parsed.attachmentId) evt.attachmentId = parsed.attachmentId;
+      if (parsed.sourceFilename) evt.sourceFilename = parsed.sourceFilename;
+      if (parsed.rejectionReason) evt.rejectionReason = parsed.rejectionReason;
+      if (parsed.rejectionLimit != null) evt.rejectionLimit = parsed.rejectionLimit;
+      if (parsed.affectedUserIds) evt.affectedUserIds = parsed.affectedUserIds;
       return evt;
     });
 
@@ -420,12 +426,16 @@ function handleSizeRejection(
   }
 
   // Queue a file_rejected reverse relay event to the sender's instance
+  // Extract the filename from the sourceUrl (e.g., "https://sender/api/uploads/12345.png" → "12345.png")
+  const sourceFilename = entry.sourceUrl.split('/').pop() ?? entry.sourceUrl;
+
   const event: FederationRelayEvent = {
     eventType: 'file_rejected',
     messageId: localMsg.sourceMessageId,
     encryptionVersion: 0,
     timestamp: now,
     attachmentId: att?.id ?? entry.sourceUrl,
+    sourceFilename,
     rejectionReason: 'size_limit_exceeded',
     rejectionLimit: maxUploadSize,
     affectedUserIds,

packages/shared/src/types.ts

@@ -770,6 +770,7 @@ export interface FederationRelayEvent {
   friendship?: FederationFriendshipPayload;
   // file_rejected event fields
   attachmentId?: string;
+  sourceFilename?: string;
   rejectionReason?: string;
   rejectionLimit?: number;
   affectedUserIds?: string[];

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" />