- Add Configure button on built-in provider cards (openai, anthropic,
gemini, ollama, etc.) to set API key and default model via web UI
- Store overrides as `llm_builtin_overrides` setting (per-provider
key/model map) using the existing generic settings k/v API
- Add LlmBuiltinOverride struct in settings.rs; resolve in
resolve_registry_provider() with priority:
env var > selected_model > llm_builtin_overrides[id] > default
- Restore provider's configured model to selected_model on provider
switch, so /model command always takes precedence at runtime
- Fix fetch-models button in built-in configure mode: use hardcoded
base_url from BUILTIN_PROVIDERS instead of the hidden form field
- Add edit support for custom providers with pre-filled dialog
- Show current model on active and configured provider cards
- Convert add/edit provider form to a modal dialog
- Sync selected_model when editing or deleting an active custom provider