feat: strategy builder

backend/routers/strategy_builder.py

@@ -179,6 +179,30 @@ def suggested_profile(scenario: ScenarioIn):
     return infer_natural_greek_profile(scenario.spot_shock_pct, scenario.iv_level_shift, scenario.horizon_days)
 
 
+class ReplayRequest(BaseModel):
+    symbol: str
+    legs: List[LegIn]
+    start_date: str
+    end_date: str
+    contract_size: float = DEFAULT_CONTRACT_SIZE
+
+
+@router.post("/replay")
+def replay(req: ReplayRequest):
+    """Day-by-day mark-to-market of these exact legs against REAL accumulated Saxo
+    history between two dates — not a scenario, a replay of what actually happened.
+    See services.strategy_replay for why it's a distinct thing from /price's scenario
+    pricing (which prices a hypothetical spot/IV shock, not real historical quotes)."""
+    from services.strategy_replay import replay_position
+    try:
+        return replay_position(
+            req.symbol, [leg.dict() for leg in req.legs], req.start_date, req.end_date,
+            contract_size=req.contract_size,
+        )
+    except ValueError as e:
+        raise HTTPException(status_code=404, detail=str(e))
+
+
 @router.post("/optimize")
 def optimize(req: OptimizeRequest):
     if req.constraints.max_legs > 4: