Module resolution 

Single source of truth for resolving the per-session execution “dance”: provider-name derivation + provider_type + global auxiliary models + gold config, mapped into the snapshot structs the agent loop consumes.

These resolution rules are load-bearing invariants — the resolved provider name (session model ref, falling back to config.provider) and the global (never session-bound) auxiliary model fallback. They were previously hand-rolled at every spawn/resume site; centralizing them here keeps the rules consistent by construction. The builder is pure orchestration over the existing atomic helpers, so behavior is identical to the hand-rolled copies.

Functions

resolve_resume_config_snapshot

Resolve the ResumeConfigSnapshot for a session from a cloned Config snapshot + provider registry.