refactor(documents): drop duplicate sender/receiver in list rows

The desktop document-list row showed sender/receiver twice — once
side-by-side in the middle column and again stacked in the right
column. Stack the middle-column block vertically (the side-by-side
grid wasted horizontal space and competed with the larger thumbnail)
and remove the now-redundant copy from the right column.

The middle-column block keeps the search-match highlighting, which the
right-column copy never had.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

frontend/src/lib/components/DocumentRow.svelte

@@ -77,8 +77,8 @@ function safeTagColor(color: string | null | undefined): string {
 					</p>
 				{/if}
 
-				<!-- Sender / receivers — desktop only -->
-				<div class="mt-2 mb-2 hidden gap-4 font-sans text-xs text-ink-2 sm:grid sm:grid-cols-2">
+				<!-- Sender / receivers — desktop only, stacked -->
+				<div class="mt-2 mb-2 hidden flex-col gap-1 font-sans text-xs text-ink-2 sm:flex">
 					<div>
 						<span class="font-bold tracking-wide text-ink-3 uppercase">{m.docs_list_from()}</span>
 						<span class="ml-1">
@@ -158,26 +158,6 @@ function safeTagColor(color: string | null | undefined): string {
 				<div>
 					{doc.documentDate ? formatDate(doc.documentDate) : '—'}
 				</div>
-				<div>
-					<span class="font-bold tracking-wide text-ink-3 uppercase">{m.docs_list_from()}</span>
-					<span class="ml-1">
-						{#if doc.sender}
-							{doc.sender.displayName}
-						{:else}
-							<span class="text-ink-3 italic">{m.docs_list_unknown()}</span>
-						{/if}
-					</span>
-				</div>
-				<div>
-					<span class="font-bold tracking-wide text-ink-3 uppercase">{m.docs_list_to()}</span>
-					<span class="ml-1">
-						{#if doc.receivers && doc.receivers.length > 0}
-							{doc.receivers.map((r) => r.displayName).join(', ')}
-						{:else}
-							<span class="text-ink-3 italic">{m.docs_list_unknown()}</span>
-						{/if}
-					</span>
-				</div>
 				<div class="flex items-start gap-2">
 					<ProgressRing percentage={item.completionPercentage} />
 					<div class="flex h-9 items-center">