LibreChat: Shared-agent editor can globally delete owner's file records — breaks owner's other private agents

LibreChat is an enhanced ChatGPT clone that supports multiple AI providers. In versions up to and including 0.8.3, a shared-agent editor can delete file records through `DELETE /api/files` that the owner has reused across multiple agents. The deletion removes the file globally — not just from the shared agent — breaking the owner's other private agents that reference the same `file_id`. The private agent retains a stale `file_id` reference that no longer resolves. A shared-agent editor can destroy files that the owner uses across multiple agents. The owner's private agents — which the attacker has no access to — break silently with stale `file_id` references. This is a cross-agent integrity violation: editing access to one agent should not affect another. Version 0.8.4 contains a patch.