feat: Binance WS, news client, and social client

Add ThreadedWebsocketManager-based BinanceWSClient for real-time price
streaming, NewsClient for CryptoPanic/NewsAPI fetching with coin filtering,
and SocialClient for Reddit post retrieval with keyword filtering and
simple keyword-based sentiment scoring. Includes unit tests for news and
social clients (4/4 passing).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

data/binance_ws.py

@@ -0,0 +1,51 @@
+import threading
+import logging
+from binance import ThreadedWebsocketManager
+
+logger = logging.getLogger(__name__)
+
+class BinanceWSClient:
+    def __init__(self, api_key: str, api_secret: str):
+        self.api_key = api_key
+        self.api_secret = api_secret
+        self.twm = None
+        self.prices: dict[str, float] = {}
+        self._lock = threading.Lock()
+
+    def start(self, symbols: list[str]):
+        self.twm = ThreadedWebsocketManager(
+            api_key=self.api_key, api_secret=self.api_secret
+        )
+        self.twm.start()
+        streams = [s.lower() + "@miniTicker" for s in symbols]
+        self.twm.start_multiplex_socket(
+            callback=self._handle_message, streams=streams
+        )
+        logger.info(f"WebSocket started for {len(symbols)} symbols")
+
+    def _handle_message(self, msg):
+        if msg.get("e") == "error":
+            logger.error(f"WebSocket error: {msg}")
+            return
+        data = msg.get("data", msg)
+        if "s" in data and "c" in data:
+            with self._lock:
+                self.prices[data["s"]] = float(data["c"])
+
+    def get_price(self, symbol: str) -> float | None:
+        with self._lock:
+            return self.prices.get(symbol)
+
+    def get_all_prices(self) -> dict[str, float]:
+        with self._lock:
+            return dict(self.prices)
+
+    def update_symbols(self, symbols: list[str]):
+        if self.twm:
+            self.stop()
+            self.start(symbols)
+
+    def stop(self):
+        if self.twm:
+            self.twm.stop()
+            logger.info("WebSocket stopped")