Fix dashboard backtest detail, deterministic backtest seeds, paper trader fees, live node crash guard

Backtest detail: openDetail() now fetches full backtest JSON from the API
instead of showing "Full trade data not in summary". Renders equity curve
chart + full trade history table with 100 rows.

Backtest reproducibility: replaced hash(key) with fixed per-strategy seeds.
Python's hash() is randomized per process (PYTHONHASHSEED), causing wildly
different results for same strategy across runs. Now deterministic.

Server: added total_trades and sortino to /api/backtests summary response.

Paper trader: fixed Avellaneda-Stoikov simulate using TAKER_FEE instead of
MAKER_FEE. Lowered OBI signal threshold from 5bps to 1.5bps for flat markets.

Live node: added None-guard in get_mark_prices — Hyperliquid testnet API
sometimes returns null, crashing the node. Wrapped in try/except.

live/node.py

@@ -64,11 +64,18 @@ def get_fills(addr):
     return r.json() if r.status_code==200 else []
 
 def get_mark_prices():
-    r = requests.post(TESTNET_API, json={"type":"metaAndAssetCtxs"}, timeout=10)
-    data = r.json(); prices = {}
-    for i,u in enumerate(data[0]["universe"]):
-        if u["name"] in ("BTC","ETH"): prices[u["name"]] = float(data[1][i]["markPx"])
-    return prices
+    try:
+        r = requests.post(TESTNET_API, json={"type":"metaAndAssetCtxs"}, timeout=10)
+        data = r.json()
+        if not data or data[0] is None or "universe" not in data[0]:
+            return {}
+        prices = {}
+        for i,u in enumerate(data[0]["universe"]):
+            if u["name"] in ("BTC","ETH"):
+                prices[u["name"]] = float(data[1][i]["markPx"])
+        return prices
+    except Exception:
+        return {}
 
 def get_orderbook(coin):
     """Get best bid, best ask, and mid from L2 orderbook."""