Research ledger for cash flows and option settlement

[Pigbibi]

Scope

• Extend the research ledger for dividend accrual/payment, splits, external deposits and withdrawals, receivables, and flow-neutral returns. Duplicate or missing economic events fail closed; legacy records remain readable.
• Record option assets/liabilities, trades, restricted cash, protected spreads, and expiration-only physical settlement with cash/share reconciliation.

Verification

• PYTHONPATH=src python3 -m pytest -q tests/test_lifecycle_performance_store.py: 54 passed, 33 subtests passed.
• Ruff and git diff --check passed before commit.
• The UES research consumer wrote synthetic trials and a separate QPK-only process read back a fixed local snapshot. This does not mean UES has adopted a normal QPK dependency release.

Limits and dependency

• Draft research contract. Synthetic accounting checks do not establish historical strategy performance, promotion eligibility, or live trading permission.
• American early assignment and broker-specific settlement are not covered; the implemented physical settlement applies at expiration.
• The companion UsEquityStrategies PR is required for the research replay consumer. No deployment or trading was performed.

Companion consumer: QuantStrategyLab/UsEquityStrategies draft PR #523. Its current CI fails at import because the ordinary UES QPK dependency remains pinned to the pre-contract commit; this is an explicit integration gate, not evidence that the local fixed-snapshot readback failed.