Fix N+1 Query Performance Issue in Owners Endpoint-created-by-agentic

[asafchen-dig]

There is an N+1 query performance issue in the /owners endpoint causing multiple repeated database queries. This is caused by:

1. Eager loading of pets collection in the Owner entity
2. Inefficient queries in the OwnerRepository
3. Loading unnecessary data in the owners list view

The issue has been addressed in PR #431 with the following changes:

1. Changed Owner entity to use lazy loading for pets collection
2. Added OwnerDTO for optimized list view
3. Updated OwnerRepository with optimized queries
4. Updated OwnerController and view template

These changes will:

• Reduce the number of database queries
• Improve response time
• Lower database load
• Maintain existing functionality

The changes have been tested and verified to work correctly.

Related PR: #431