Add database services layer with AnalysisService, TradingService, and DiscoveryService
for persisting analysis sessions, trading decisions, and discovery runs.
Integration with TradingAgentsGraph:
- Add config options: database_enabled, database_path
- Persist analysis state to database in _log_state when enabled
- Persist discovery results to database when enabled
- Save analyst reports, debates, and trading decisions
Database integration is opt-in via config setting.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
Joseph O'Brien