架构规则与指南

To maintain code quality, maintainability, and hexagonal separation, all code contributions MUST follow these rules:

1. Strict Layering Boundaries

• use_cases/: Pure business logic. MUST NOT import fastapi, sqlalchemy, or provider implementations directly.
• routers/: Transport layer. Translates HTTP requests to use case inputs and maps domain exceptions to HTTP status codes.
• concurrency.py: Blocking synchronous operations (SQLAlchemy, Pandas, yfinance) MUST be executed via run_sync().

2. Identifier Strategy

• Always use (asset_id, ticker, exchange, currency) resolution via DatabaseService.get_asset_context().
• Do not assume a ticker uniquely identifies a stock globally (TSLA can be a stock or an ETP). Always respect ISIN mappings.

3. Data Integrity & Validation

• All provider inputs MUST pass through ValidationLayer checks before being exposed to end users.
• Do not mask symptoms by returning dummy fallbacks or swallowing exceptions silently.