TaskGet should support returning full task metadata

Summary

TaskUpdate accepts arbitrary metadata via the metadata parameter (e.g., structured handoff data, workflow state, calibration records), but TaskGet only returns a summary projection: subject, status, description, blocks, and blockedBy. There's no way to read back the metadata through the Task API.

Current behavior

TaskUpdate(taskId="1", metadata={"handoff": {"produced": [...], "decisions": [...]}})
# writes successfully

TaskGet(taskId="1")
# returns: subject, status, description, blocks, blockedBy
# metadata is NOT included

Expected behavior

TaskGet should support returning the full task JSON, including metadata and owner fields. Either:

• Option A: Always include metadata and owner in TaskGet output
• Option B: Add an optional parameter like include_metadata: true to opt into the full response

Workaround

Currently the only way to read task metadata is to read the raw JSON file from disk:

cat ~/.claude/tasks/{team_name}/{task_id}.json | python3 -c "import json,sys; print(json.dumps(json.load(sys.stdin).get('metadata',{})))"

This works but bypasses the Task API abstraction and requires knowing the file path convention.

Use case

In multi-agent workflows, agents store structured handoff data in task metadata (produced files, key decisions, areas of uncertainty). Downstream agents and the orchestrator need to read this metadata to inform subsequent phases. The TaskGet summary view is insufficient for this — the metadata contains the substantive work product.