Daily sweep (15:00 UTC) emails a warm, personal "checking in" message
to users who signed up 3-14 days ago and still have no paired screen,
nudging them toward activation. Once per user, reuses the Graph
transport (services/email.js) via the existing fromName/rawSubject
options.
- New service services/activationNudge.js, started from server.js.
Self-correcting daily scheduler (recompute next 15:00 UTC each run;
no node-cron dependency).
- Eligibility (Option B, workspace-aware): created 3-14 days ago,
activation_nudge_sent_at IS NULL, COALESCE(email_alerts,1)=1 (only
an explicit opt-out of 0 is excluded; NULL/unset still qualify), and
ZERO devices owned by the user OR present in any workspace they
belong to. The workspace check avoids nudging engaged team members.
- Idempotency: activation_nudge_sent_at, stamped after send; paired
sentinel-1 backfill so the first sweep can't blast the dormant
legacy base. Only genuinely-new signups become eligible.
- GATE: HOSTED_INSTANCE=true (positive hosted signal, NOT !selfHosted).
A daily bulk sweep would be far worse to leak than a single email, so
a self-hoster who configured Graph but missed SELF_HOSTED won't blast
their user base. Unset -> neither scheduled nor sent. Documented in
.env.example.
