Functions for managing the default ellmer Chat object used by dsprrr.
When no Chat is explicitly provided to a module or run() call, these
functions determine which Chat to use.
Details
The default Chat is resolved in this order:
Explicit
options(dsprrr.default_chat = chat_object)Auto-detection from environment variables:
OPENAI_API_KEY→ellmer::chat_openai()ANTHROPIC_API_KEY→ellmer::chat_claude()
Error with helpful setup instructions