Adds the built-in structured_assertions scorer to local and worker execution, with no user registration or Rust dependency. Recipes share the SDK-core contract: named assertion results, partial scores, thresholds, typed errors, and bounded parsing/execution.
Also includes the previously merged durable activation display ancestry fix. Worker metadata reports 0.10.3.
Validated with the full Go suite and race-enabled release CI. Runtime rollout is tracked separately in arunreddy/agnt5#3220.