- Adds GET /v3/action/hosted_file/hash/{sha256}/download for direct content-addressable storage access.
- Updates V3 authentication dependencies to support 'api_key' in the query parameter (alias 'api_key').
- Implements auth_method: 'api_key' for machine-to-machine requests that provide a valid key but no user/account context.
- Updates GUIDE__V3_FRONTEND_API.md with the new endpoint and auth options.
- Updates download_file_action to automatically resolve container IDs (like event_file) to the underlying hosted_file.
- Updates GUIDE__V3_FRONTEND_API.md to document the 'ID Vision' standard for downloads.
- Resolves 404 errors observed when frontend passed event_file IDs to the hosted_file download endpoint.
