4e9916b3e5
An empty or omitted providers dict is now the valid dormant posture: the adapter mounts with zero routes and no catalog entries, registers routes the moment the llm-pi-ai settings section supplies profiles, and drops them when it empties. The TUI demo mounts the adapter bare, so adding an openai/anthropic provider is purely a settings.yaml (or, next PR, web form) operation with per-request apiKeyEnv credential resolution.