Plane: Cross-Workspace Asset Duplication IDOR + WorkspaceFileAssetEndpoint and FileAssetEndpoint Missing Authorization

Plane is an open-source project management tool. Prior to 1.4.0, DuplicateAssetEndpoint fetches a source FileAsset without limiting it to the caller's workspace, allowing cross-workspace asset duplication. WorkspaceFileAssetEndpoint and the legacy FileAssetEndpoint omit workspace authorization, allowing authenticated users to read, create, modify, or delete assets in workspaces where they are not members. Separately, WorkspaceViewViewSet.retrieve lacks the authorization decorator used by its sibling actions, exposing an unauthorized workspace-view read surface. This issue is fixed in 1.4.0.