AnythingLLM: Legacy mobile device tokens bypass multi-user workspace scoping after mode migration

AnythingLLM is an application that turns pieces of content into context that any LLM can use as references during chatting. Prior to 1.13.0, an approved mobile device token created in single-user mode can survive single-user -> multi-user migration even when the device record has userId = null. In multi-user mode, that stale token is still accepted by the mobile authentication middleware. Because no user is attached to the request, downstream mobile handlers fall back to unscoped data-access branches and return workspaces and workspace content without per-user filtering. This permits a pre-migration mobile token to enumerate a workspace assigned only to another user and retrieve victim-owned thread metadata and chat content in multi-user mode. This vulnerability is fixed in 1.13.0.