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

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

BREAKING CHANGE: per-currency API fields replaced with single RUB Money.

prisma/migrations/20261108000001_rub_only_resync_now/migration.sql

@@ -0,0 +1,3 @@
+-- RUB-only: snapshots were dropped by the previous migration; clearing the hourly
+-- schedule makes the next scheduler tick rebuild them instead of waiting for the term.
+DELETE FROM "TbankSyncWork" WHERE "scopeKey" = 'hourly';