feat: add all-accounts portfolio pages

Reuse account sections and group securities with per-account holdings.

Use Mantine Select to preserve filters and reset pagination on scope changes.

Document component reuse guardrails and cover routes, grouping and scope switching.

src/entities/brokerage-event/ui/BrokerageEventCard.tsx

@@ -19,6 +19,7 @@ const BrokerageEventCard: FC<BrokerageEventCardProps> = (props) => {
 		date,
 		event.dateKind === "registry" ? t("events.dateKind.registry") : null,
 		event.isin,
+		event.account?.name,
 	]
 		.filter(Boolean)
 		.join(" · ");

src/entities/brokerage-event/ui/BrokerageEventsPreview.tsx

@@ -36,7 +36,15 @@ const BrokerageEventsPreview: FC<BrokerageEventsPreviewProps> = (props) => {
 			{events.state === "loaded"
 				? events.items.map((event) => (
 						<BrokerageEventCard
-							key={`${event.type}-${event.date}-${event.ticker}`}
+							key={JSON.stringify([
+								event.account?.id,
+								event.type,
+								event.date,
+								event.instrumentUid,
+								event.figi,
+								event.ticker,
+								event.logoName,
+							])}
 							event={event}
 						/>
 					))