Use hub exchange instances for calculator contract precision.

Load enabled instances from settings, fetch market info via /api/hub/market, and apply exchange-specific amount and price precision in trend and roll calculators.

Co-authored-by: Cursor <cursoragent@cursor.com>

manual_trading_hub/hub.py

@@ -831,7 +831,8 @@ class TrendCalculatorBody(BaseModel):
     add_upper: float = Field(gt=0)
     take_profit: float = Field(gt=0)
     dca_legs: int = Field(default=5, ge=1, le=20)
-    contract_size: float = Field(default=1.0, gt=0)
+    exchange_id: str = "0"
+    base: str = "ETH"
 
 
 class RollAddLegBody(BaseModel):
@@ -848,6 +849,25 @@ class RollCalculatorBody(BaseModel):
     take_profit: float = Field(gt=0)
     add_legs: list[RollAddLegBody] = Field(default_factory=list, max_length=3)
     legs_done: int = Field(default=0, ge=0, le=3)
+    exchange_id: str = "0"
+    base: str = "ETH"
+
+
+@app.get("/api/calculator/exchanges")
+def api_calculator_exchanges():
+    from hub_calculator_market_lib import list_calculator_exchanges
+
+    return {"ok": True, "data": list_calculator_exchanges()}
+
+
+@app.get("/api/calculator/market")
+def api_calculator_market(exchange_id: str = "0", base: str = "ETH"):
+    from hub_calculator_market_lib import get_calculator_market
+
+    data, err = get_calculator_market(exchange_id, base)
+    if err:
+        return JSONResponse({"ok": False, "msg": err}, status_code=400)
+    return {"ok": True, "data": data}
 
 
 @app.post("/api/calculator/trend")
@@ -864,7 +884,8 @@ def api_calculator_trend(body: TrendCalculatorBody):
         add_upper=body.add_upper,
         take_profit=body.take_profit,
         dca_legs=body.dca_legs,
-        contract_size=body.contract_size,
+        exchange_id=body.exchange_id,
+        base=body.base,
     )
     if err:
         return JSONResponse({"ok": False, "msg": err}, status_code=400)
@@ -884,6 +905,8 @@ def api_calculator_roll(body: RollCalculatorBody):
         take_profit=body.take_profit,
         add_legs=[leg.model_dump() for leg in body.add_legs],
         legs_done=body.legs_done,
+        exchange_id=body.exchange_id,
+        base=body.base,
     )
     if err:
         return JSONResponse({"ok": False, "msg": err}, status_code=400)