ChatPayloadBuilder caught EModelEndpoint.valueOf for custom endpoint
names (OpenRouter, Deepseek, etc.) and silently sent endpoint=agents,
producing 403 "Forbidden: Insufficient permissions" on the server.
Type endpoint identity as String end-to-end, add EndpointClassifier to
derive endpointType / key / modelDisplayLabel from /api/config, and
propagate the dispatch fields to all five chat-send sites in
ChatViewModel (doSendMessage, editUserMessage, editAiMessage,
regenerateMessageNow, continueGenerationNow). A normalization shim in
ConversationMapper converts legacy enum-name rows in the Room cache
back to wire format on read.
Verified end-to-end against a docker LibreChat v0.8.5 instance with
OpenRouter user_provided keys; built-in .env Anthropic regression also
passes.
