feat: an unpaid cart's files are kept 2 days, a paid order's 30

Files are uploaded before payment so the price and the security check use
the file itself, but an abandoned cart kept them for 30 days. Now a finished
upload is held 2 days, a quote waiting for review 7, an approved quote 2 more
to be paid, and the paid order keeps its originals for 30 days from upload.
A payment never starts for files that are gone; one under way holds them a
day. Files attached to an order take the order's window.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

app/artwork.py

@@ -67,7 +67,8 @@ def submit_files(c, order, body, identity, kind, actor):
     for ref in body.files:
         c.execute('INSERT INTO dtf_local.order_files(id,order_id,upload_id,item_index,kind,note,created_by) VALUES(%s,%s,%s,%s,%s,%s,%s)',
                   (uuid4(),order['id'],ref.upload_id,ref.item_index,kind,body.note,actor))
-        c.execute('UPDATE dtf_local.uploads SET expires_at=LEAST(expires_at,%s) WHERE id=%s', (expiry,ref.upload_id))
+        # The order's window, whatever the upload's own hold was.
+        c.execute('UPDATE dtf_local.uploads SET expires_at=%s WHERE id=%s', (expiry,ref.upload_id))
     c.execute('UPDATE dtf_local.orders SET version=version+1,updated_at=now() WHERE id=%s', (order['id'],))
     if kind == 'final':
         # Artwork approval, not commercial quote approval, starts original cleanup.