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

sandbox/RESEARCH_API_USAGE.md

@@ -77,6 +77,54 @@ print(df.head())
 - `"ticker"` - Market identifier
 - `"period_seconds"` - Period in seconds
 
+## Building a Scanner Universe with get_ticker_24h
+
+**Always pre-filter symbols before fetching OHLC for multiple tickers.** The per-script bar budget is 2M bars; fetching all ~1800 Binance symbols would exhaust it immediately. Use `get_ticker_24h` to get a ranked, filtered list of symbols with no OHLC budget cost, then run per-symbol analysis only on the filtered set.
+
+```python
+from dexorder.api import get_api
+import asyncio
+
+api = get_api()
+
+# Get top 50 most liquid Binance spot symbols by USD volume (no bar budget used)
+universe = asyncio.run(api.data.get_ticker_24h(
+    "BINANCE",
+    limit=50,
+    market_type="spot",
+    min_std_quote_volume=10_000_000  # filter to $10M+ daily USD volume
+))
+print(f"Universe: {len(universe)} symbols")
+
+# Now fetch OHLC only for the filtered set
+for ticker in universe["ticker"]:
+    df = asyncio.run(api.data.historical_ohlc(
+        ticker=ticker,
+        period_seconds=86400,  # daily bars for a scanner
+        start_time="2024-01-01",
+        end_time="2025-01-01",
+        extra_columns=["volume"]
+    ))
+    print(f"[Data] {ticker}: {len(df)} bars")
+```
+
+### Filter parameters
+
+```python
+# All BTC pairs on Binance
+df = asyncio.run(api.data.get_ticker_24h("BINANCE", base_asset_contains="BTC"))
+
+# Top 100 perp markets with $50M+ daily volume
+df = asyncio.run(api.data.get_ticker_24h(
+    "BINANCE", limit=100, market_type="perp", min_std_quote_volume=50_000_000
+))
+
+# All symbols on Coinbase
+df = asyncio.run(api.data.get_ticker_24h("COINBASE"))
+```
+
+Returned DataFrame is sorted by `std_quote_volume` (USD-normalized) descending. Symbols without a USD rate have `std_quote_volume = NaN` and appear last. Full column list: `ticker`, `exchange_id`, `base_asset`, `quote_asset`, `last_price`, `price_change_pct`, `quote_volume_24h`, `std_quote_volume`, `bid_price`, `ask_price`, `open_24h`, `high_24h`, `low_24h`, `volume_24h`, `num_trades`, `timestamp_ms`.
+
 ## Using the Charting API
 
 The charting API provides styled financial charts with OHLC candlesticks and technical indicators.