Task Authoring

1. Choose the public domain, visible scene_id, and objective contract.
2. Add the implementation at src/trace_tasks/tasks/<domain>/<scene_id>/<objective_contract>.py.
3. Add scene and task prompt templates under src/trace_tasks/resources/prompts/<domain>/....
4. Add domain or scene defaults under src/trace_tasks/resources/configs/domains/<domain>/.
5. Construct a deterministic scene, query, render specification, execution trace, typed answer, and projected annotation.
6. Reject ambiguous or non-unique instances instead of weakening constraints.
7. Add focused tests and task documentation.

Use shared helpers only when they preserve the same semantic contract across their callers. Domain-specific refinements are documented under docs/domains/.