subscrStart, warrantyStart, and maintainedOn are written to Firestore as
Timestamps like the other date fields here, but were missing from
_TIMESTAMP_FIELD_NAMES, so they weren't being converted back to ISO
strings on read.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Two-tier (warning/critical) threshold config per device — restarts/week,
RSSI floor, free-heap floor, CPU temp ceiling, plus an offline timeout
used for both a client-computed health status icon and the Health tab
chart's gap detection. Purely advisory for now: no server-side
email/push alerting infra exists yet, so email_on_threshold and
push_on_crash_boot are placeholders for that future work.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
bonaminandClaude Sonnet 5