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/integrations/tbank/decimal.ts

@@ -1,4 +1,6 @@
-import { Decimal } from '../../common/decimal';
+import type { Money } from '../../common/money.types';
+
+import { Decimal, formatDecimal } from '../../common/decimal';
 
 const MISSING_PROTO_COMPONENT = 0;
 
@@ -6,6 +8,12 @@ const NANO = 1_000_000_000n;
 
 export type ProtoDecimal = { nano?: number | string; units?: number | string };
 
+export function rubMoney(value?: ProtoDecimal & { currency?: string }): Money | null {
+  return value?.currency?.trim().toUpperCase() === 'RUB'
+    ? { currency: 'RUB', value: formatDecimal(decimal(value)) }
+    : null;
+}
+
 export function decimal(value: ProtoDecimal): Decimal {
   return {
     value: BigInt(value.units ?? MISSING_PROTO_COMPONENT) * NANO + BigInt(value.nano ?? MISSING_PROTO_COMPONENT),