Design a provider-neutral model runner

[askmy-stack]

Summary

Define and implement the narrow provider-neutral interface used by model-backed probes.

Acceptance criteria

• Runner interface separates provider transport from probe evaluation
• At least one provider adapter is implemented behind the interface
• Model/provider/version and run configuration are recorded in results
• Timeouts, retries, and cost-sensitive limits are configurable
• No provider SDK is required for deterministic-only users
• Unit tests use fakes rather than live model calls