zero v0.1.2-preview.1: agent status snapshots

Agent status snapshots

zero status shows active agents and their latest observed briefs. Use --all
to include paused and inactive agents, or --agent EXACT-SLUG for schedule,
source counts, pending suggestions, and visible research/discovery progress.

zero status
zero status --agent EXACT-AGENT-SLUG --usage
zero status --json
zero status --out ./status.json

• JSON uses the standard zero/v1 envelope with a zero/status/v1 snapshot.
• File exports are atomic, owner-only, and never overwrite existing files.
• Partial snapshots retain useful data and return exit 1. Unknown progress is
  not reported as completed or healthy.
• The overview defaults to 10 selected agents. Provider inventory and accounting
  pagination limits remain explicit.
• Brief titles now support the current styled-div markup as well as headings.

Verified with 21 command-boundary tests, including an installed CLI fixture
workflow, plus live read-only overview/detail, usage, and JSON-file checks using
the macOS bundle outside the repository. No paid research was triggered.

Download the Apple Silicon archive and SHA256SUMS together, verify the checksum,
and keep the extracted folder intact. The archive includes its runtime.
This is an unsigned, unnotarized developer preview of an unofficial client.
See the README for login, installation, and provider limitations.