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>

tests/test_news_client.py

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+import pytest
+from data.news_client import NewsClient
+
+@pytest.fixture
+def client():
+    return NewsClient(cryptopanic_key="test", newsapi_key="test")
+
+def test_parse_cryptopanic_response(client):
+    raw = {
+        "results": [
+            {"title": "Bitcoin hits new high", "published_at": "2026-03-20T10:00:00Z",
+             "currencies": [{"code": "BTC"}], "kind": "news",
+             "votes": {"positive": 10, "negative": 2}},
+            {"title": "ETH upgrade coming", "published_at": "2026-03-20T09:00:00Z",
+             "currencies": [{"code": "ETH"}], "kind": "news",
+             "votes": {"positive": 5, "negative": 1}},
+        ]
+    }
+    articles = client.parse_cryptopanic(raw)
+    assert len(articles) == 2
+    assert articles[0]["coin"] == "BTC"
+    assert articles[0]["title"] == "Bitcoin hits new high"
+
+def test_get_news_for_coin_filters(client):
+    articles = [
+        {"coin": "BTC", "title": "BTC news", "sentiment_votes": {"positive": 5, "negative": 1}},
+        {"coin": "ETH", "title": "ETH news", "sentiment_votes": {"positive": 3, "negative": 3}},
+    ]
+    btc_news = client.filter_by_coin(articles, "BTC")
+    assert len(btc_news) == 1
+    assert btc_news[0]["coin"] == "BTC"

tests/test_social_client.py

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+import pytest
+from data.social_client import SocialClient
+
+def test_analyze_reddit_posts():
+    client = SocialClient(reddit_client_id="x", reddit_secret="x", reddit_user_agent="x")
+    posts = [
+        {"title": "Bitcoin is amazing! Going to the moon!", "score": 100, "num_comments": 50},
+        {"title": "BTC crash incoming, sell everything now", "score": 20, "num_comments": 10},
+        {"title": "Bitcoin steady at 40k, not bad", "score": 50, "num_comments": 30},
+    ]
+    result = client.simple_sentiment(posts)
+    assert "positive" in result
+    assert "negative" in result
+    assert "neutral" in result
+    assert result["positive"] + result["negative"] + result["neutral"] == len(posts)
+
+def test_keyword_match():
+    client = SocialClient(reddit_client_id="x", reddit_secret="x", reddit_user_agent="x")
+    posts = [
+        {"title": "Bitcoin BTC going up"},
+        {"title": "Ethereum news today"},
+        {"title": "BTC and ETH analysis"},
+    ]
+    filtered = client.filter_posts_by_coin(posts, "BTC")
+    assert len(filtered) == 2