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>

requirements.txt

@@ -0,0 +1,11 @@
+streamlit>=1.30.0
+python-binance>=1.0.19
+pandas>=2.1.0
+ta>=0.11.0
+plotly>=5.18.0
+anthropic>=0.40.0
+praw>=7.7.0
+httpx>=0.27.0
+apscheduler>=3.10.0
+python-dotenv>=1.0.0
+pytest>=8.0.0