Add Ticker24h support: hourly market snapshots with USD-normalized volume filtering

gateway/knowledge/api-reference.md

@@ -247,6 +247,63 @@ class DataAPI(ABC):
         """
         pass
 
+    @abstractmethod
+    async def get_ticker_24h(
+        self,
+        exchange: str,
+        limit: Optional[int] = None,
+        min_std_quote_volume: Optional[float] = None,
+        market_type: Optional[str] = None,
+        base_asset_contains: Optional[str] = None,
+    ) -> pd.DataFrame:
+        """
+        Retrieve 24h rolling market stats for all symbols on an exchange.
+
+        Data is refreshed hourly by the ingestor pipeline. Use this to build a
+        pre-filtered symbol universe before running a scanner — it avoids requesting
+        per-symbol OHLC data for thousands of symbols.
+
+        Args:
+            exchange: Exchange name (e.g., "BINANCE", "COINBASE", "KRAKEN")
+            limit: If set, return only the Top N symbols By Volume. None = return all.
+            min_std_quote_volume: Exclude symbols with USD volume below this threshold.
+            market_type: Filter by market type: "spot" or "perp". None = return all.
+            base_asset_contains: Filter to symbols whose base asset contains this string
+                                  (case-insensitive). E.g., "BTC" matches "BTC/USDT".
+
+        Returns:
+            DataFrame sorted by std_quote_volume descending (NULLs last). Columns:
+            - ticker: Full ticker (e.g., "BTC/USDT.BINANCE")
+            - exchange_id: Exchange name
+            - base_asset: Base currency (e.g., "BTC")
+            - quote_asset: Quote currency (e.g., "USDT")
+            - last_price: Last traded price in quote currency
+            - price_change_pct: 24h price change as percentage (e.g. 2.5 = +2.5%)
+            - quote_volume_24h: Raw 24h volume in quote asset
+            - std_quote_volume: quote_volume_24h normalized to USD (NaN if conversion unknown)
+            - bid_price, ask_price: Current best bid/ask (NaN if not provided by exchange)
+            - open_24h, high_24h, low_24h: 24h OHLC prices (NaN if not provided)
+            - volume_24h: Base-asset volume (NaN if not provided)
+            - num_trades: 24h trade count (NaN if not provided)
+            - timestamp_ms: Snapshot timestamp in milliseconds
+
+            Returns empty DataFrame if no data is available (e.g., not yet fetched).
+
+        Examples:
+            # Top 50 most liquid Binance spot symbols
+            df = await api.data.get_ticker_24h("BINANCE", limit=50, market_type="spot")
+
+            # All BTC pairs with at least $10M daily volume
+            df = await api.data.get_ticker_24h("BINANCE",
+                                                base_asset_contains="BTC",
+                                                min_std_quote_volume=10_000_000)
+
+            # Build a scanner universe: all Binance symbols, sorted by volume
+            universe = await api.data.get_ticker_24h("BINANCE")
+            top_100 = universe.head(100)["ticker"].tolist()
+        """
+        pass
+
 ```