feat(stream): bubble footer with timestamp and inline favorite/download

Match the Figma 4206-6509 card layout for /browse: every bubble now
renders a bottom row with the publish timestamp on the left and the
action buttons on the right. Image, album, video, text and link cards
show only the FavoriteButton; file-document cards show the
FavoriteButton plus a new BubbleAttachmentDownloadButton sized to
match. Removes the absolute-positioned favorite from the default
variant, drops the right-aligned timestamp block, and strips the inline
per-row download button from FileDocBubble's default variant since the
download now lives in the footer. The 'latest' masonry variant is
untouched so the home page continues to use LatestFileCard's existing
internal footer.

src/components/messageStream/bubbles/FileDocBubble.tsx

@@ -18,29 +18,11 @@ import { useToast } from "../../Toast";
 import { FavoriteButton } from "../../../favorites/FavoriteButton";
 import type { MessageBubbleVariant } from "../MessageBubble";
 
-function AttachmentRow({ postId, att }: { postId: string; att: Attachment }) {
-  const { t } = useI18n();
-  const { showToast } = useToast();
-  const { showSaveToAlbumGuide } = useSaveToAlbumGuide();
+function AttachmentRow({ att }: { postId: string; att: Attachment }) {
   const { Icon, color } = fileIcon({ mime: att.mime, filename: att.filename });
   const displayFilename = filenameWithExtension(att.filename, att.mime);
-  const [isDownloading, setIsDownloading] = useState(false);
   const [previewFailed, setPreviewFailed] = useState(false);
 
-  const handleDownload = async () => {
-    if (isDownloading) return;
-    setIsDownloading(true);
-    try {
-      await downloadAttachment(postId, att.id, displayFilename);
-      const mediaKind = mediaSaveKindFromAttachment(att);
-      if (mediaKind) showSaveToAlbumGuide(mediaKind);
-    } catch {
-      showToast(t("downloadFail"), "error");
-    } finally {
-      setIsDownloading(false);
-    }
-  };
-
   const isImage = att.kind === "image" || att.mime.startsWith("image/");
   const previewUrl =
     att.thumbnailUrl ?? att.posterUrl ?? (isImage ? att.url : undefined);
@@ -84,25 +66,9 @@ function AttachmentRow({ postId, att }: { postId: string; att: Attachment }) {
           })()}
         </div>
         <div className="text-[12px] font-medium leading-[19.2px] text-[#A8A9AE]">
-          {isDownloading ? t("downloading") : formatBytes(att.sizeBytes)}
+          {formatBytes(att.sizeBytes)}
         </div>
       </div>
-      <button
-        type="button"
-        onClick={handleDownload}
-        disabled={isDownloading}
-        className="flex h-10 w-10 shrink-0 items-center justify-center rounded-full bg-[#191921] text-white transition hover:bg-[#22232D] disabled:cursor-wait"
-        aria-label={
-          isDownloading ? t("downloading") : `Download ${att.filename}`
-        }
-        aria-busy={isDownloading}
-      >
-        {isDownloading ? (
-          <LoaderCircle className="h-5 w-5 animate-spin" strokeWidth={2.3} />
-        ) : (
-          <DownloadCloudIcon className="h-6 w-6" />
-        )}
-      </button>
     </div>
   );
 }