feat: add paper trading capital controls — API endpoint + UI with presets, fix status/metrics to read real state, fix migration duplicates

services/trading/app.py

@@ -50,6 +50,13 @@ class ConfigUpdateRequest(BaseModel):
     absolute_position_cap: Optional[float] = None
     active_pool_minimum: Optional[float] = None
     micro_trading_enabled: Optional[bool] = None
+    max_open_positions: Optional[int] = None
+
+
+class CapitalRequest(BaseModel):
+    """Body for PUT /api/trading/capital."""
+
+    initial_capital: float
 
 
 class BacktestRequest(BaseModel):
@@ -255,6 +262,60 @@ async def resume_engine() -> dict[str, bool]:
     return {"paused": False}
 
 
+@app.put("/api/trading/capital")
+async def set_capital(body: CapitalRequest) -> dict[str, Any]:
+    """Set or reset the paper trading capital.
+
+    Allocates the given amount as initial capital, splitting between
+    active pool and reserve pool based on the current reserve_siphon_pct.
+    """
+    if engine is None:
+        raise HTTPException(503, "Engine not initialised")
+
+    capital = body.initial_capital
+    if capital <= 0:
+        raise HTTPException(400, "initial_capital must be positive")
+
+    reserve_pct = engine.config.reserve_siphon_pct
+    reserve = capital * reserve_pct
+    active = capital - reserve
+
+    ps = engine.portfolio_state
+    previous = {
+        "total_value": ps.total_value if ps else 0.0,
+        "active_pool": ps.active_pool if ps else 0.0,
+        "reserve_pool": ps.reserve_pool if ps else 0.0,
+    }
+
+    from services.trading.models import PortfolioState
+    engine.portfolio_state = PortfolioState(
+        total_value=capital,
+        cash=capital,
+        active_pool=active,
+        reserve_pool=reserve,
+    )
+
+    # Record in reserve pool ledger
+    if engine.pool:
+        try:
+            await engine.pool.execute(
+                "INSERT INTO reserve_pool_ledger (amount, balance_after, trigger_type, notes) "
+                "VALUES ($1, $2, 'capital_reset', $3)",
+                reserve, reserve,
+                f"Capital set to ${capital:,.2f} (active=${active:,.2f}, reserve=${reserve:,.2f})",
+            )
+        except Exception:
+            pass  # Non-critical
+
+    return {
+        "initial_capital": capital,
+        "active_pool": active,
+        "reserve_pool": reserve,
+        "reserve_siphon_pct": reserve_pct,
+        "previous": previous,
+    }
+
+
 # ---------------------------------------------------------------------------
 # Decision Audit Trail
 # ---------------------------------------------------------------------------