WinRacing V51 Supreme Decision Engine 51.0.0

ADDED
- Complete ChairmanSupremeDecisionEngineV51 class.
- V51 standalone/dashboard entry.
- V51 unified JSON API.
- Read-only V50 source validation.
- Supreme confidence calibration, decision tiers, risk penalty and daily summary.
- Optional filesystem JSON snapshot.

UNCHANGED
- V44-V50 score formulas.
- V44-V50 betting suggestion logic.
- Existing database schema and data.
- Existing V50 Dashboard/API behavior.

REMOVED
- Three V51 echo Ready placeholder files were replaced by operational implementations.
