refactor!: support RUB only (WealthLedger/main#55)

Filter non-RUB data at ingest, collapse per-currency collections into single RUB Money, drop currency from TbankPortfolioValuePoint, remove NON_RUB_ACTIVITY and screener currency filter.

BREAKING CHANGE: per-currency API fields replaced with single RUB Money; stock screener currency param removed.

src/modules/investments/upcoming-events/upcoming-event.mapper.ts

@@ -61,10 +61,10 @@ function projectedMoney(
   value: string,
   currency: string | undefined,
 ): UpcomingEventDto['projectedAmount'] {
-  const normalizedCurrency = currency?.trim().toUpperCase();
-  if (!normalizedCurrency) return null;
+  // RUB-only: projected income in other currencies is filtered out.
+  if (currency?.trim().toUpperCase() !== 'RUB') return null;
   return {
-    currency: normalizedCurrency,
+    currency: 'RUB',
     value: formatDecimal(multiply(quantity, decimalFromString(value))),
   };
 }