feat(voice): emit callback handoff notification on guardian-wait timeout

[noanflaherty]

Summary

• When a caller opts into callback during guardian-wait and the wait times out or the call disconnects, a notification is now emitted to the guardian so the callback intent is not silently dropped
• Adds emitAccessRequestCallbackHandoff() helper with idempotency guard (in-memory flag + deterministic dedupeKey) to prevent duplicate notifications from timeout + transport-close race
• Includes trusted-contact member reference in the notification payload when the caller maps to an existing member record
• Adds deterministic fallback copy template for the new ingress.access_request.callback_handoff source event
• Notification-only handoff — no auto-callback execution, no schema migration, no new persistence beyond normal notification/event behavior

Test plan

• Relay-server tests: callback opt-in + timeout emits handoff notification
• Relay-server tests: no callback opt-in + timeout does NOT emit handoff
• Relay-server tests: callback opt-in + transport close emits handoff
• Relay-server tests: timeout then transport-close race emits only one handoff (idempotency)
• Relay-server tests: payload includes requesterMemberId when member exists
• Relay-server tests: payload omits member reference when no member exists
• Copy-composer tests: renders caller identity (name + phone, phone only, name only, unknown)
• Copy-composer tests: includes request code when present
• Copy-composer tests: includes trusted-contact member reference when present
• Copy-composer tests: telegram/sms channels get deliveryText fallback

Original prompt

/Users/noaflaherty/Repos/vellum-ai/vellum-assistant/.private/plans/voice-access-request-callback-handoff-notification-one-pr-plan-2026-03-01.md

🤖 Generated with Claude Code

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[noanflaherty]

@codex review

[noanflaherty]

@devin review

[devin-ai-integration]

✅ Devin Review: No Issues Found

Devin Review analyzed this PR and found no potential bugs to report.

View in Devin Review to see 4 additional findings.

[noanflaherty]

@codex review this PR again — the previous issues have been fixed in commit 7d6fdd8

[noanflaherty]

@devin review this PR again — the previous issues have been fixed in commit 7d6fdd8

[chatgpt-codex-connector]

Codex Review: Didn't find any major issues. Swish!

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[noanflaherty]

The Codex P1 feedback about restricting callback handoff member mapping to trusted contacts was already addressed in the merged code. The emitAccessRequestCallbackHandoff method gates requesterMemberId on member.status === 'active' && member.policy === 'allow' (line 1452), which ensures only trusted contacts are identified — revoked/pending/denied members correctly leave requesterMemberId as null. No follow-up PR needed.