feat: expose instrument isin in portfolio positions

src/tbank/portfolio.service.ts

@@ -44,7 +44,7 @@ const types: Record<string, string> = {
 
 type CachedSnapshot = { snapshot: PortfolioDto; storedAt: number };
 type CachedMetadata = {
-  value: { ticker?: string; name?: string } | null;
+  value: { ticker?: string; name?: string; isin?: string } | null;
   storedAt: number;
 };
 
@@ -209,6 +209,7 @@ export class PortfolioService {
       currentValue,
       averagePurchasePrice,
       absoluteReturn,
+      isin: metadata?.isin?.trim() || null,
     };
   }
 
@@ -236,7 +237,7 @@ export class PortfolioService {
   ) {
     const lookup = async (
       key: string,
-      fetch: () => Promise<{ ticker?: string; name?: string } | null>,
+      fetch: () => Promise<{ ticker?: string; name?: string; isin?: string } | null>,
     ) => {
       const cached = this.metadata.get(key);
       if (cached && Date.now() - cached.storedAt <= metadataForMs)