Initial commit: NextGen PPR System

- FastAPI backend with JWT authentication
- MySQL database with full schema
- Docker Compose orchestration
- CSV data import for 43,208 airports and 519,999 aircraft
- Complete PPR management API
- Modernized replacement for PHP-based system

backend/app/db/__init__.py

@@ -0,0 +1 @@
+# Empty __init__.py files to make Python packages

backend/app/db/session.py

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+from sqlalchemy import create_engine
+from sqlalchemy.ext.declarative import declarative_base
+from sqlalchemy.orm import sessionmaker
+from app.core.config import settings
+
+engine = create_engine(
+    settings.database_url,
+    pool_pre_ping=True,
+    pool_recycle=300,
+    echo=False,  # Set to True for SQL debugging
+)
+
+SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
+
+Base = declarative_base()