feat(document): remove the visible Originaltext line from DocumentDate

DocumentDate rendered an "Originaltext: <raw>" secondary line for
UNKNOWN/SEASON/APPROX dates, gated by a showRaw prop. Drop the visible
line, the showRaw prop, the showRawLine derived, and the now-unused
date_original_label message import. The raw prop stays — it still feeds
the SEASON word in formatDocumentDate, which only ever maps a fixed
German season token (never emits raw text), so no XSS surface remains.

Update both DocumentRow call sites to drop the now-gone showRaw={false}
and the comment that justified it. Remove the two DocumentDate tests
that asserted on the deleted DOM sink (the UNKNOWN secondary line and
its XSS-escaping); the DAY/MONTH coverage stays.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/src/lib/document/DocumentRow.svelte

@@ -164,15 +164,10 @@ function safeTagColor(color: string | null | undefined): string {
 				<!-- Mobile-only metadata -->
 				<div class="mt-3 grid grid-cols-2 gap-x-4 gap-y-1 font-sans text-xs text-ink-2 sm:hidden">
 					<div>
-						<!-- Product decision (#666): raw provenance (meta_date_raw) is shown on the
-						     document DETAIL page, never in list/search rows — list rows surface only the
-						     honest label to keep scan-rows compact. showRaw={false} enforces this; the
-						     DocumentListItem payload also intentionally omits metaDateRaw. -->
 						<DocumentDate
 							iso={doc.documentDate}
 							precision={doc.metaDatePrecision}
 							end={doc.metaDateEnd}
-							showRaw={false}
 						/>
 					</div>
 					<div class="flex items-start gap-2">
@@ -194,7 +189,6 @@ function safeTagColor(color: string | null | undefined): string {
 						iso={doc.documentDate}
 						precision={doc.metaDatePrecision}
 						end={doc.metaDateEnd}
-						showRaw={false}
 					/>
 				</div>
 				<div>