0.9.0

Retro feedback loop (ffb-cgx Phases 0–5) plus refresh-job docs and review fixes.

• Add the Sleeper waivers card to the refresh job runbook (#80)
• Keep point-in-time projections and advice for the retro feedback loop (#81)
• Join prediction ledgers to weekly actuals for retro history (#82)
• Calibrate sit/start projections in shadow for the retro loop. (#83)
• Add a walk-forward calibration backtest and promotion gate. (#84)
• Promote calibrated sit/start advice behind the gate (ffb-cgx.5) (#85)
• Document the Yahoo sign-in gate and refresh exit 126. (#86)
• Score one pre-kickoff ledger roster for history and backtest (#87)
• Backfill 2024–2025 calibration priors (ffb-cgx.6) (#88)