Add project setup: dependencies, config, and package scaffolding

- requirements.txt with all core dependencies (streamlit, binance, ta, anthropic, praw, etc.)
- .env.example template for all required API keys
- .gitignore covering secrets, caches, db files, and logs
- config.py loading env vars with trading defaults and signal weights
- tests/conftest.py with sys.path fix for imports
- Empty __init__.py files for tests, data, agents, engine, dashboard, scheduler packages

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

config.py

@@ -0,0 +1,36 @@
+import os
+from dotenv import load_dotenv
+
+load_dotenv()
+
+# API Keys
+BINANCE_API_KEY = os.getenv("BINANCE_API_KEY", "")
+BINANCE_SECRET = os.getenv("BINANCE_SECRET", "")
+CRYPTOPANIC_API_KEY = os.getenv("CRYPTOPANIC_API_KEY", "")
+NEWS_API_KEY = os.getenv("NEWS_API_KEY", "")
+TWITTER_BEARER_TOKEN = os.getenv("TWITTER_BEARER_TOKEN", "")
+REDDIT_CLIENT_ID = os.getenv("REDDIT_CLIENT_ID", "")
+REDDIT_SECRET = os.getenv("REDDIT_SECRET", "")
+REDDIT_USER_AGENT = os.getenv("REDDIT_USER_AGENT", "crypto_signal_bot/1.0")
+ANTHROPIC_API_KEY = os.getenv("ANTHROPIC_API_KEY", "")
+
+# Defaults
+DB_PATH = os.path.join(os.path.dirname(__file__), "crypto_signals.db")
+LOG_DIR = os.path.join(os.path.dirname(__file__), "logs")
+TOP_N_COINS = 50
+SURGE_VOLUME_MULTIPLIER = 3.0
+MAX_POSITIONS = 5
+INITIAL_CAPITAL = 200.0
+STOP_LOSS_PCT = -0.08
+TAKE_PROFIT_1_PCT = 0.15
+TAKE_PROFIT_2_PCT = 0.25
+MIN_POSITION_USD = 15.0
+ANALYSIS_INTERVAL_MINUTES = 15
+
+# Default weights
+DEFAULT_WEIGHTS = {
+    "technical": 0.6,
+    "news": 0.2,
+    "social": 0.1,
+    "ai": 0.1,
+}