Add Context Store Foundation

Status

Registration/resolution facade implemented.

Source Of Truth

Start from ../direction.md.

The relevant model is:

Context stores sync truth.
Collections shape truth.
Initiatives coordinate work.
Workspaces open local views.
Changes implement repo-owned slices.

Goal

Add the smallest core foundation for context stores without making the store layer know about initiatives, collections, workspaces, or repo-local changes.

Locked Direction

• Support one backend for the first slice: a Git/local checkout backend.
• Treat the actual context store root as a user-chosen local Git checkout or synced folder.
• Do not hide real team context stores under XDG data by default.
• Store the machine-local registry under global data: $XDG_DATA_HOME/openspec/context-stores/registry.yaml.
• Store portable context-store identity inside the store root: <store-root>/.openspec-store/store.yaml.
• Start with backend identity/config, strict validation, path helpers, and registry/metadata read-write helpers.
• Add a thin registration/resolution facade before initiative CLI wiring so callers do not manipulate raw registry and metadata YAML directly.
• Do not reimplement the TypeScript or Node filesystem APIs as the public store interface.
• Do not add initiative, collection, workspace-open, sync, pull, push, or CLI behavior in this slice.

Initial Shape

Machine-local registry:

version: 1
stores:
  acme-context:
    backend:
      type: git
      local_path: /Users/me/repos/acme-context
      remote: [email protected]:acme/context.git
      branch: main

Portable metadata in the store root:

version: 1
id: acme-context

Likely Repo Slice

• Add src/core/context-store/foundation.ts.
• Add src/core/context-store/registry.ts.
• Add src/core/context-store/index.ts.
• Export the core context-store foundation from src/core/index.ts.
• Add focused tests under test/core/context-store/.
• Keep specs untouched until a behavior/API contract is deliberately surfaced.

Implemented Facade Slice

• Added registerContextStore(...).
• Added listRegisteredContextStores(...).
• Added resolveRegisteredContextStore(...).
• Registration writes portable store metadata when missing, validates existing metadata when present, and merges/updates the machine-local registry.
• Resolution validates that the registry id matches the store-root metadata id.
• No Git clone, pull, push, sync, workspace state, collection manifest, or CLI behavior was added.