Functions for managing the default ellmer Chat object used by dsprrr.
When no Chat is explicitly provided to dsp() or module(), 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