Adds a daily IBKR Flex Web Service → Wealthfolio ingestion path alongside
the existing T212 / IE / Fidelity providers. Uses the ibflex library;
mandatory broker-vs-WF position reconciliation built in from day one to
prevent the silent-drift class of bug we hit with InvestEngine on 2026-05-26.
Account is currently empty so the initial backfill step is a no-op until
the first IBKR trade lands.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
