Context Store Project Roots And Schema-Led Initiatives Tasks

• Create Item 15 work-item tracking notes.
• Record the product decision that context stores should behave like OpenSpec roots for config and schema resolution, but not as implementation repos by default.
• Define the context-store root layout, including .openspec-store/, openspec/config.yaml, openspec/schemas/, and initiatives/.
• Decide the config key for the default initiative schema, with initiative_schema as the preferred next-release-safe direction.
• Decide whether initiative schemas share openspec/schemas/ with a usage: initiative discriminator or use a separate namespace while reusing the artifact graph format.
• Add or design the built-in product-initiative schema for high-level requirements and design artifacts.
• Define brief.md as the sparse creation seed and decide whether it sits outside the artifact graph or is represented as an already-complete artifact.
• Change initiative create from hardcoded six-file generation to sparse initiative.yaml plus brief.md creation.
• Add initiative artifact status resolution rooted at context-store/initiatives/<id>/.
• Add initiative artifact instructions output that returns schema guidance, template content, dependencies, output path, and existing paths.
• Ensure store-local config context and rules can be read for initiative artifact instructions without confusing repo-local change config.
• Guard planning-home resolution so context stores with openspec/config.yaml do not silently become repo-local implementation homes.
• Update initiative create --json, human output, and next-command guidance for sparse creation and iterative artifacts.
• Update tests that currently assert the MVP six-file initiative shape.
• Add compatibility tests proving old six-file initiatives still list and show.
• Add tests for context-store local schemas and store config defaults.
• Update beta docs and agent guidance to stop telling agents to edit every initiative markdown file immediately after creation.
• Record migration behavior and a note that Item 5's six-file MVP shape has been superseded by this schema-led sparse model.