Validate model availability before run execution

[RPaolino]

Description

Currently, the code execution starts without verifying whether all required models are present. This can lead to runs being initiated even when one or more models are missing, resulting in failures during execution.

Expected Behavior

Before starting a run, the system should:

1. Check that all models specified in the configuration are available.
2. If any model is missing:
   • Prevent the run from starting.
   • Provide a clear and informative error message indicating which models are missing.

Current Behavior

• The run starts without validation.
• Missing models cause errors during execution rather than being caught early.

Proposed Solution

Implement a pre-run validation step that Iterates through the list of required models.