This pull request standardizes how avatar URLs are constructed and handled throughout the codebase. The main change is to always use the fileToGatewayUrl function for avatar files, removing fallback logic to manifest URLs. Additionally, support for a new "mirror" file source is introduced, enabling avatar files to be fetched from HTTP mirrors with proper URL construction. Type definitions are updated to reflect this new source and its required fields.

Avatar URL handling improvements:

• All avatar URL assignments now exclusively use fileToGatewayUrl, removing fallback to manifest URLs in functions such as fetchDirectory, fetchDnpRequest, fetchRegistryIpfsData, getOptimismConfig, and getAll in various files. [1] [2] [3] [4] [5] [6] [7] [8]

• The repository logic is updated so that avatar file entries are always constructed, and mirror sources are handled explicitly, removing previous logic that set manifest.avatarUrl directly when using mirrors.

Distributed file source enhancements:

• The DistributedFileSource type now includes "mirror", and the DistributedFile interface is updated to require filename and packageHash for mirror sources, with clarifying comments. [1] [2]

• The fileToGatewayUrl utility function is enhanced to generate proper URLs for mirror sources, using the base mirror URL, package hash, and filename, and returning an empty string if required fields are missing.