Initial commit: Clean Mold Cost Calculator application

- Flask-based mold cost calculation application
- PostgreSQL database with SQLAlchemy ORM
- Docker/Podman containerization
- Comprehensive documentation in docs/
- Clean, organized codebase without obsolete files
- Production-ready deployment configuration
- Enhanced pytest configuration with coverage reporting
- Master/Development branch structure

app/extensions.py

@@ -0,0 +1,16 @@
+from flask_sqlalchemy import SQLAlchemy
+from flask_login import LoginManager
+from flask_migrate import Migrate
+from flask_wtf.csrf import CSRFProtect
+from flask_limiter import Limiter
+from flask_limiter.util import get_remote_address
+from flask_caching import Cache
+from flask_mail import Mail
+
+db = SQLAlchemy()
+login_manager = LoginManager()
+migrate = Migrate()
+csrf = CSRFProtect()
+limiter = Limiter(key_func=get_remote_address)
+cache = Cache()
+mail = Mail()