cli: manage workgroups and team membership for routing automation

[mblua]

Refs #233.

Agents cannot currently create/manage workgroups and team membership fully from the CLI. Routing depends on workgroup/team metadata, so a throwaway E2E environment cannot be created without GUI steps.

This blocked #233 smoke because a test Codex target must be discoverable/reachable by the sender under the same host/workgroup.

Proposed CLI shape:

agentscommander.exe workgroup list --project <path>
agentscommander.exe workgroup add --project <path> --name <wg-N-slug> [--from-template <name>]
agentscommander.exe workgroup remove --project <path> --name <wg-N-slug>
agentscommander.exe team list --project <path> --workgroup <wg-N>
agentscommander.exe team add-member --project <path> --workgroup <wg-N> --team <team> --agent <agent> [--coordinator]
agentscommander.exe team remove-member --project <path> --workgroup <wg-N> --team <team> --agent <agent>

Acceptance criteria:

• workgroup add creates the same on-disk layout the GUI creates, including messaging/, BRIEF.md, and team metadata.
• team add-member updates routing metadata so list-peers shows the added peer as reachable from another team member.
• After setup, send --to <peer> --command clear --mode wake reaches the peer instead of failing routing.
• Remove commands refuse destructive cleanup while live sessions exist.

How this unblocks automation:
Agents can create a disposable workgroup, add sender/target agents, and run end-to-end messaging/PTy smoke without GUI setup.

[mblua]

Cross-link: #309 covers the third missing CLI piece — create-agent-matrix (provisioning a real Matrix agent with Role.md, memory/, plans/, skills/, role template, and the .claude + RTK hook wiring the GUI flow already does).

Together, #241 (workgroups + team membership) + #309 (matrix agents) close the gap that lets an agent or coordinator bootstrap a full project structure from CLI without GUI steps.