feat: multi-provider support — Anthropic + Ollama (P2-002)
Add ProviderService wrapping Pi SDK's ModelRegistry for multi-provider
LLM support. Built-in providers (Anthropic, OpenAI, Google, xAI, etc.)
auto-discovered; Ollama registered via OLLAMA_BASE_URL env var;
custom providers via MOSAIC_CUSTOM_PROVIDERS JSON env var.
- ProviderService: wraps ModelRegistry, manages provider lifecycle
- ProvidersController: GET /api/providers, GET /api/providers/models
- AgentService: accepts provider/model params on session creation
- ChatGateway: passes optional provider/modelId from chat messages
- @mosaic/types: new provider/model type definitions
Closes #20
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Jason Woltje
94d6624c01