Create Artifact (MCP-native storage)

Register your deliverable using mcp__plugin_dh_backlog__artifact_register. This is the ONLY correct storage path for plan artifacts. Do NOT use Write to disk and do NOT return content inline.

Why disk writes and inline returns are wrong

• Disk writes produce a file only accessible from the root worktree. Worktree-isolated agents and CI environments cannot reach ~/.dh/... paths via filesystem — they must use artifact_read(item_id, artifact_type) over MCP.
• Inline returns are truncated by the task-notification summary when the agent runs as a background-dispatched task. The orchestrator receives a partial summary, not the full document.

MCP-native storage uploads content to a GitHub issue comment where any agent — regardless of worktree or environment — can retrieve it via artifact_read.

Correct invocation (verified against backlog_core/server.py:2385)