Explore Initiative-Hosted Target-Bound Change Artifacts Tasks

• Create Item 18 work-item tracking notes.
• Reframe Item 18 from generic change-home configuration to initiative-hosted target-bound change artifacts.
• Audit commands, templates, validation, archive, apply, completion, and docs for repo-local openspec/changes/ assumptions.
• Define user-facing naming for initiative work items, briefs, target-bound changes, artifact homes, and editable targets.
• Decide whether initiative-hosted artifacts can graduate into executable changes, and which target metadata is required first.
• Decide the configuration or opt-in surface for repo-local versus initiative-hosted artifacts.
• Define how openspec new change selects and reports the artifact home, implementation target, initiative link, and action context.
• Define how initiative linking and workspace guidance discover artifact homes and target repo mappings.
• Decide how initiative-hosted target-bound changes bind to repo specs, implementation roots, branches, and local checkout paths.
• Decide validation, apply, archive, sync, and conflict behavior for initiative-hosted target-bound changes.
• Define the agent JSON contract for work target, artifact home, implementation target, allowed edit roots, unsupported lifecycle commands, and next commands.
• Record compatibility behavior for existing repo-local and workspace-local changes.
• Produce a recommendation, opt-in/config examples, affected command list, and go/no-go criteria for implementation.