fix: import models in init_db to ensure table creation

app/core/database.py

@@ -23,5 +23,8 @@ async def get_db() -> AsyncSession:
             await session.close()
 
 async def init_db():
+    # Import all models here to ensure they are registered with Base.metadata
+    from app.models import User, Organization, OrganizationMember, Integration, Issue, AuditLog  # noqa
+    
     async with engine.begin() as conn:
         await conn.run_sync(Base.metadata.create_all)