test: cover ErrorHTML, Layouts, MapLive.Components, CoreComponents, Accounts
- ErrorHTML: explicit 400 path + 401/403/999 delegation.
- Layouts.body_class/1 returns the expected light/dark theme classes.
- MapLive.Components: map_container + slideover_panel exercising all
connection_status variants, loading state, tracked_callsign clear
button, and view-mode radios.
- CoreComponents: icon (found + fallback), button, label, error,
flash (info + error + close=false), checkbox input, JS composers.
- Accounts: get_user_by_email{_and_password}, get_user!, register_user
happy-path + error paths, change_* changesets, session-token
round-trip.
Refactor: DeviceIdentification.maybe_refresh_devices splits its nested
logic into fetch_most_recent_device/0, to_datetime/1, and
refresh_if_stale/2 — each a multi-clause function matching on shape.
Coverage 68.28 → 69.56%.