Fix Hyperliquid API: asset names come from universe array, not context dicts

The metaAndAssetCtxs endpoint returns asset names in a parallel
universe array — asset contexts don't have a "name" field.
Fixed the API module to index by the universe array properly.

Also added get_mark_price() helper. Tested against testnet:
BTC funding 0.00125% per 8h, mark $62,873.

common/hyperliquid_api.py

@@ -1,14 +1,19 @@
 """
 Hyperliquid API utilities.
 
-Direct REST calls to Hyperliquid info endpoint for data
+Direct REST calls to Hyperliquid's info endpoint for data
 not yet covered by the NautilusTrader adapter (funding rates,
 predicted fundings, asset contexts).
+
+API structure:
+  POST /info {"type": "metaAndAssetCtxs"}
+  Returns [universe_meta, asset_contexts]
+  - universe_meta["universe"] = list of {"name": "BTC", ...}
+  - asset_contexts[i] corresponds to universe[i]
 """
 import requests
 from typing import Any
 
-
 TESTNET_API = "https://api.hyperliquid-testnet.xyz/info"
 MAINNET_API = "https://api.hyperliquid.xyz/info"
 
@@ -19,44 +24,47 @@ def _post(api_url: str, payload: dict) -> Any:
     return resp.json()
 
 
-def get_asset_contexts(testnet: bool = True) -> list[dict]:
+def get_asset_contexts(testnet: bool = True) -> dict[str, dict]:
     """
     Fetch asset contexts including current funding rates.
-    Returns list of per-asset dicts with keys:
-    funding, openInterest, markPx, oraclePx, premium, dayNtlVlm, etc.
+    Returns dict keyed by asset name (BTC, ETH, SOL, etc.)
+    with values containing funding, markPx, openInterest, etc.
     """
     api = TESTNET_API if testnet else MAINNET_API
     data = _post(api, {"type": "metaAndAssetCtxs"})
-    # data[0] = universe, data[1] = asset contexts
-    if isinstance(data, list) and len(data) >= 2:
-        return data[1]
-    return []
+
+    if not isinstance(data, list) or len(data) < 2:
+        return {}
+
+    universe = data[0].get("universe", [])
+    ctxs = data[1]
+
+    result = {}
+    for i, asset_info in enumerate(universe):
+        if i < len(ctxs):
+            name = asset_info.get("name", "")
+            if name:
+                result[name] = ctxs[i]
+    return result
 
 
 def get_funding_rate(asset_name: str, testnet: bool = True) -> float | None:
     """
     Get the current funding rate for a specific asset.
-    Funding is paid every 8 hours. Positive = longs pay shorts.
+    Funding is a per-8-hour rate. Positive = longs pay shorts.
+    Multiply by 3 * 365 for approximate annualized rate.
     """
     ctxs = get_asset_contexts(testnet=testnet)
-    for ctx in ctxs:
-        if isinstance(ctx, dict) and ctx.get("name") == asset_name.upper():
-            funding_str = ctx.get("funding", "0")
-            return float(funding_str)
+    ctx = ctxs.get(asset_name.upper())
+    if ctx:
+        return float(ctx.get("funding", 0))
     return None
 
 
 def get_all_funding_rates(testnet: bool = True) -> dict[str, float]:
     """Get funding rates for all assets on Hyperliquid."""
     ctxs = get_asset_contexts(testnet=testnet)
-    rates = {}
-    for ctx in ctxs:
-        if isinstance(ctx, dict):
-            name = ctx.get("name", "")
-            funding_str = ctx.get("funding", "0")
-            if name:
-                rates[name] = float(funding_str)
-    return rates
+    return {name: float(ctx["funding"]) for name, ctx in ctxs.items()}
 
 
 def get_predicted_funding(asset_name: str, testnet: bool = True) -> float | None:
@@ -65,11 +73,22 @@ def get_predicted_funding(asset_name: str, testnet: bool = True) -> float | None
     Uses the predictedFundings endpoint.
     """
     api = TESTNET_API if testnet else MAINNET_API
-    data = _post(api, {"type": "predictedFundings"})
+    try:
+        data = _post(api, {"type": "predictedFundings"})
+    except Exception:
+        return None
+
     if isinstance(data, list):
         for item in data:
-            if isinstance(item, dict) and item.get("name") == asset_name.upper():
-                # Return the Hyperliquid-specific prediction
-                predicted = item.get("funding", "0")
-                return float(predicted)
+            if isinstance(item, dict) and item.get("name", "").upper() == asset_name.upper():
+                return float(item.get("funding", 0))
+    return None
+
+
+def get_mark_price(asset_name: str, testnet: bool = True) -> float | None:
+    """Get the current mark price for an asset."""
+    ctxs = get_asset_contexts(testnet=testnet)
+    ctx = ctxs.get(asset_name.upper())
+    if ctx:
+        return float(ctx.get("markPx", 0))
     return None