- Introduced `InvestmentActivityDetector` to mark internal investment activity as excluded from cashflow and assign appropriate labels.
- Added `exclude_from_cashflow` flag to `entries` and `investment_activity_label` to `transactions` with migrations.
- Implemented rake tasks to backfill and clear investment activity labels.
- Updated `PlaidAccount::Investments::TransactionsProcessor` to map Plaid transaction types to labels.
- Included comprehensive test coverage for new functionality.