[Bug] Workflow @agent-name does not resolve when agent profile display_name differs, emitting no p tag and never waking ACP

[Tony-ooo]

Reproduction

A scheduled workflow in a channel contains a normal agent mention:

steps:
  - action: send_message
    text: "@OMP perform the scheduled check"

The channel member is the agent named OMP, but its Nostr user profile has display_name: "OMP-Mac" (the platform-created runtime/profile label). The workflow is accepted and the relay posts the kind:9 message, but it contains no p tag for the agent:

• text contains @OMP
• event contains buzz:workflow=true
• event contains the channel h tag
• event is relay-signed
• event has no p=<OMP pubkey>

ACP agent wake is p-tag gated, so the agent never receives the workflow task and no result is produced. This reproduced on a hosted channel on 2026-08-09.

Root cause

crates/buzz-relay/src/workflow_sink.rs::resolve_mention_pubkeys resolves workflow text against users.display_name only. It has no awareness of the agent's configured/canonical name. Interactive client mention composition resolves an agent selection into a pubkey, but workflow YAML stores only free text and re-parses it later, so @OMP and OMP-Mac drift apart.

This is related to #2686 (workflow sink has a divergent mention parser), but is a distinct identity-resolution failure: even plain @Name text at a valid boundary fails when the configured agent name differs from its profile display name.

Expected behavior

A workflow addressed to the channel agent's canonical name should emit the same p tag as an interactive mention and wake that agent, regardless of a runtime/profile display-name suffix.

Suggested direction

Use one canonical mention-resolution service for both interactive composition and workflow execution. For workflow text, resolve exact channel-scoped aliases from both:

1. the user display name; and
2. the agent's configured/canonical name.

Keep the current fail-closed behavior for ambiguous aliases: if an alias maps to multiple pubkeys, emit no p tag and return a visible workflow validation/error result instead of silently posting an unwakeable task. Add regression coverage for agent name != profile display_name, including OMP / OMP-Mac.