feat: attachment component

[zyx1121]

WinLab version of shadcn's base-nova attachment, for portal's receipt, trip, approve and door-sound files.

• One size and one orientation (a row): 40px icon or thumbnail, name, a detail line, actions. Dropped sm / xs, vertical, scroll-snap group and the shimmer utility.
• It keeps its own outline like an input (a control, not a card): rounded-menu with p-1 around the rounded-control media, per the concentric rule.
• States idle (dashed), uploading (pulsing name, faded media), error (destructive border, media and detail), done.
• AttachmentTrigger makes the row clickable; AttachmentAction is the ghost icon button; AttachmentGroup stacks rows with gap-2.
• CI smoke installs it.

Verified on sandbox with WebKit, light and dark: the three demo rows render in each state.

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