- Add type query param to GET /accounts/:accountId/positions endpoint
- Backend filters T-Bank portfolio positions by instrument type before pagination
- Each instrument type (share, bond, etf, fund) has its own frontend table with
independent cursor-based pagination and skeleton loading
- Groups with no positions are automatically hidden
- Cache key includes type for correct per-type caching
- Remove centralized positions pagination state from BrokerAccountDetailPage
- 94 backend tests / 112 frontend tests pass
