feat: add project config and database connection

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/core/database.py

@@ -0,0 +1,25 @@
+from typing import Generator
+
+from sqlalchemy import create_engine
+from sqlalchemy.orm import DeclarativeBase, Session, sessionmaker
+
+from app.core.config import settings
+
+engine = create_engine(
+    settings.database_url,
+    pool_pre_ping=True,
+    pool_recycle=1800,
+)
+SessionLocal = sessionmaker(bind=engine)
+
+
+class Base(DeclarativeBase):
+    pass
+
+
+def get_db() -> Generator[Session, None, None]:
+    db = SessionLocal()
+    try:
+        yield db
+    finally:
+        db.close()