refactor: Centralize database session management in a shared dependency module

routes/parameters.py

@@ -4,10 +4,10 @@ from fastapi import APIRouter, Depends, HTTPException
 from pydantic import BaseModel, ConfigDict, field_validator
 from sqlalchemy.orm import Session
 
-from config.database import SessionLocal
 from models.distribution import Distribution
 from models.parameters import Parameter
 from models.scenario import Scenario
+from routes.dependencies import get_db
 
 router = APIRouter(prefix="/api/parameters", tags=["parameters"])
 
@@ -45,17 +45,6 @@ class ParameterRead(ParameterCreate):
     id: int
     model_config = ConfigDict(from_attributes=True)
 
-# Dependency
-
-
-def get_db():
-    db = SessionLocal()
-    try:
-        yield db
-    finally:
-        db.close()
-
-
 @router.post("/", response_model=ParameterRead)
 def create_parameter(param: ParameterCreate, db: Session = Depends(get_db)):
     scen = db.query(Scenario).filter(Scenario.id == param.scenario_id).first()