feat: add diagnostic log endpoint for revisions and implement download functionality

Introduced a new endpoint `GET /revisions/{revision_id}/diagnostic-log` to retrieve detailed diagnostic logs for specific revisions. Implemented the corresponding handler to generate and return the log in a structured format. Additionally, updated the frontend to include a download button for the diagnostic log, enhancing user accessibility to revision data.

web/src/lib/components/operations/OperationsRevisionsTab.svelte

@@ -13,6 +13,7 @@
 	import RefreshCw from '@lucide/svelte/icons/refresh-cw';
 	import Undo from '@lucide/svelte/icons/undo';
 	import Eye from '@lucide/svelte/icons/eye';
+	import Download from '@lucide/svelte/icons/download';
 
 	type Props = {
 		revisions: RevisionRow[];
@@ -20,10 +21,19 @@
 		onReload: () => void;
 		onOpenPreview: (rev: RevisionRow) => void;
 		onRollbackRequest: (rev: RevisionRow) => void;
+		onDownloadDiagnosticLog: (rev: RevisionRow) => void;
 		formatDate: (d?: string | null) => string;
 	};
 
-	let { revisions, revLoading, onReload, onOpenPreview, onRollbackRequest, formatDate }: Props = $props();
+	let {
+		revisions,
+		revLoading,
+		onReload,
+		onOpenPreview,
+		onRollbackRequest,
+		onDownloadDiagnosticLog,
+		formatDate
+	}: Props = $props();
 </script>
 
 <Card>
@@ -65,6 +75,14 @@
 								<Button variant="ghost" size="icon-sm" onclick={() => onRollbackRequest(rev)}>
 									<Undo class="size-3.5" />
 								</Button>
+								<Button
+									variant="ghost"
+									size="icon-sm"
+									title="Скачать диагностический лог"
+									onclick={() => onDownloadDiagnosticLog(rev)}
+								>
+									<Download class="size-3.5" />
+								</Button>
 							</div>
 						</TableCell>
 					</TableRow>