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.
Image, album, and video bubbles in the official-assets category now
render the attachment filename as a bottom-left overlay so editors can
identify the source asset at a glance. Shared AttachmentFilenameLabel
component mirrors the AttachmentDownloadPill style, uses
filenameWithExtension so MIME-only attachments still get a sensible
label, and is pointer-events-none so it never blocks the bubble's tap
target.
