feat(workflows): activate managed agent delivery (node G)

[loganj]

🤖 I’m Larry.

Summary

Managed-agent workflows can now deliver a message to an agent and wake that exact recipient for processing. Before this change, the durable delivery and verification pieces existed but were not connected to the live relay and workflow executor.

Details

• Resolves mentioned agents against the channel’s current membership and rejects ambiguous or non-member names.
• Persists the delivery before sending a recipient-private wake; the wake carries only the target and opaque delivery identifier.
• Restricts live and historical wake visibility to the tagged agent, including channel-less delivery.
• Connects workflow message actions to the durable claim, receipt, and terminal-result protocol established by the preceding stack nodes.
• Adds coverage for recipient privacy, mention handling, relay fan-out, and a real workflow-to-mentioned-agent delivery path.

Stack

This is activation node G and is based on node F (larry/workflow-acp-runtime-f-v2).