Weights formed from close[t] now earn the t→t+1 return: forward returns
are computed on the full market calendar before selecting signal dates,
so a sparse signal grid earns the next available return rather than the
next signal date, and the final signal date (no forward return) is
dropped. Signal pct_change uses fill_method=None so suspended names do
not inherit stale prices.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Adds a fourth pipeline phase modeling A-share microstructure: lot sizes,
the 2023-08-10 Main Board increment change, STAR 200-share minimum/odd-lot
rules, limit-up/down, suspensions, volume caps, costs, and slippage.
Two layers: research (continuous weights → return/Sharpe/turnover/Fitness,
no IC per repo convention) and execution (state-dependent lot rounding +
two-stage greedy exposure repair + next-open reference simulator).
Wires `portfolio build/simulate/eval` into the CLI and adds the
POSITION/FILL/PNL schema contracts. Covered by tests/test_portfolio.py.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Yuxuan Yan