Add a way to list currently running Copilot CLI sessions with their status

Feature request: Anthropic's Claude Code CLI has a ⁠claude agents --json⁠ command that lists every currently-running interactive session on the machine, each with an id, name, cwd, and status (idle/busy/waiting/blocked). This makes it possible to build an external dashboard/monitor across multiple parallel sessions (e.g. several terminal tabs or IDE panes each running their own session).
Copilot CLI has no equivalent today — ⁠--resume⁠/⁠--session-id⁠/⁠/session⁠ all operate on a specific known session for resuming, not on discovering other currently-active sessions and their live state. The closest thing is the undocumented ⁠~/.copilot/session-state//events.jsonl⁠ per-session event log, but it's internal, unversioned, and provides no "is this session still alive" signal (no PID recorded anywhere).
Ask: a ⁠copilot sessions --json⁠ (or similar) command/flag that lists currently-active sessions with at least an id, working directory, and a coarse status (busy/idle, and ideally "waiting for tool permission" as a third state) — enabling external tooling to build a multi-session status dashboard the same way it's possible for Claude Code today.

Beginnen Sie mit der Untersuchung der vorhandenen Sitzungssteuerungen (--resume, --session-id und /session) sowie der undokumentierten ~/.copilot/session-state//events.jsonl-Logs, die in der Issue beschrieben sind. Ermitteln Sie, wie aktive Sitzungen und ihr Live-Zustand identifiziert werden können, und definieren Sie anschließend den Abschluss anhand einer JSON-Auflistung, die für jede aktive Sitzung deren id, Arbeitsverzeichnis und einen groben Status meldet.