What is the maximum storage limit for files within ClaimWizard?

There is no (reasonable) limit on file storage. You can have unlimited open claims, unlimited settled/closed claims, unlimited files in a claim, and unlimited contacts / vendors / clients.

Some file types are not able to be hosted in ClaimWizard, such as Matterport scenes, but you can link that file to a claim using the Matterport tab in the Claim record.