fix: read IBKR reconciliation portfolio once

[Pigbibi]

Summary

• use the direct market-aware portfolio reader in /reconcile
• avoid passing currency and cash-mode arguments through a wrapper that already binds them

Validation

• PYTHONPATH=. PYTEST_DISABLE_PLUGIN_AUTOLOAD=1 uv run --no-sync python -m pytest -q tests/test_broker_reconciliation.py tests/test_runtime_broker_adapters.py tests/test_deployed_runtime_target_admission.py
• uv run --no-sync ruff check main.py application/broker_reconciliation.py tests/test_broker_reconciliation.py

The failed first probes completed before broker state collection and submitted no orders.