Introduces a Goals REST API (`GET/POST/PUT /api/goals` and `GET/PUT /api/goals/:id`) backed by a new `@fusion/core` goal store and typed goal types, including comprehensive route and store test coverage. Documentation on architecture and storage is updated to reflect the new domain, and a changeset Fusion-Task-Id: FN-5622 Co-authored-by: Fusion (runfusion.ai) <noreply@runfusion.ai> Fusion-Task-Id: FN-5622