e4b7f96d33
- Extract createClientFromConfig() to dispatch on provider field instead of hardcoding all tiers as AnthropicClient - Add fallback/fallbackReason metadata to ChatResponse and ChatStreamEvent so callers know when a fallback model was used - Enhance doctor check to report full model stack and warn on missing API keys for cloud providers - Log fallback warnings in NativeAgent and display them in TUI - Support tier names and local_providers entries in fallback_chain - Add 8 tests for createClientFromConfig covering all provider types