Artifact tool actions consolidated into list/read with a scope

What

When the consolidated "artifact toolset" is active, tool-result and instruction text for artifact tools is rewritten to use unified action names:

• Old action names like action "list_assets", action "read_file", and action "list_files" (used by asset_upload, asset_list, asset_delete, file_list, and file_read) now appear as action "list" or action "read", with a scope (for example scope: "assets" or scope: "files") or a path argument instead.
• Guidance that used to say action: "describe_type" now says action: "read" when this consolidated toolset is active.

Why

Collapsing several type-specific action names into a common list/read pair with a scope or path makes the artifact tool's interface simpler and more consistent for anything that reads or lists artifact content.