openspec-archive-change

Archive a completed change in the experimental workflow. **Store selection:** If the user names a store (a store is a standalone OpenSpec repo registered on this machine) or the work lives in one, run `openspec store list --json` to discover registered store ids, then pass `--store <id>` on the commands that read or write specs and changes (`new change`, `status`, `instructions`, `list`, `show`, `validate`, `archive`, `doctor`, `context`). Other commands do not take the flag. Hints printed by commands already carry the flag; keep it on follow-ups. Without a store, commands act on the nearest local `openspec/` root. **Input**: Optionally specify a change name. If omitted, check if it can be inferred from conversation context. If vague or ambiguous you MUST prompt for available changes. **Steps** 1. **If no change name provided, prompt for selection** Run `openspec list --json` to get available changes. Use the **AskUserQuestion tool** to let the user select. Show only active changes (not already archived). Include the schema used for each change if available. **IMPORTANT**: Do NOT guess or auto-select a change. Always let the user choose. 2. **Check artifact completion status** Run `openspec status --change "<name>" --json` to check artifact completion. Parse the JSON to understand: - `schemaName`: The workflow being used - `planningHome`, `changeRoot`, `artifactPaths`, and `actionContext`: path and scope context - `artifacts`: List of arti...