5.6 Add initiator-side CLI waiting for invited clients

[marwannettour]

Parent epic: #311

Summary

Support --wait and --timeout in the trusted-session start CLI flow.

Requirements

• After session creation and invitation sending, wait for invitation responses when requested.
• Display status per client.
• Respect timeout.
• Return the documented exit code.
• Provide structured JSON output when --json is used.

Acceptance criteria

• CLI wait mode reports accepted, rejected, failed, expired, and joined states.
• Timeout returns the correct exit code.
• JSON output is stable and script-friendly.