BE: conditional device import support, notification supression support during scan #1721

docs/PLUGINS_DEV_DATA_CONTRACT.md

@@ -164,7 +164,7 @@ Three optional `CurrentScan` columns, all independent of each other, control wha
 | Column | Type | Default | Meaning |
 |---|---|---|---|
 | `scanCreatesDevice` | boolean | `1` | Whether this row can originate a *new* `Devices` entry. `0` lets an enrich-only plugin (e.g. a hostname resolver) update an already-existing device's fields without ever being able to create one. |
-| `scanNotificationMode` | text (`normal` \| `quiet`) | `normal` | Whether this row's notifications are suppressed. `quiet` still writes the `Events` row (audit trail intact) but suppresses the outbound email/push. Checked two different ways depending on the event: **live**, as a per-cycle aggregate, for any event fired from a row that exists in `CurrentScan` this cycle (`New Device`, `Connected`, `Down Reconnected`, `IP Changed`) — reclassifying a plugin's row does change these going forward. Note `New Device` isn't gated on `scanPresence = 1` the way the other three are (see the flowcharts below) — it still uses this same live check, just without a presence requirement. **Frozen**, via `devAlertDown`/`devAlertEvents` seeded onto the device at creation time, for events fired from row *absence* (`Device Down`, `Disconnected`) — there's no live `CurrentScan` row to read at that moment, so reclassifying later does not retroactively change an already-created device's alert settings for these two event types. |
+| `scanNotificationMode` | text (`normal` \| `quiet`) | `normal` | Whether this row's notifications are suppressed. `quiet` always suppresses the outbound email/push; whether the `Events` row itself still gets written depends on the event. **Live** (per-cycle aggregate, reclassifying a row changes future events): `New Device`, `Connected`, `Down Reconnected`, `IP Changed` — audit trail always written. `New Device` isn't gated on `scanPresence = 1` like the other three (see flowcharts below). **Frozen** (`devAlertDown`/`devAlertEvents` seeded at device creation, reclassifying later has no retroactive effect): `Device Down`, `Disconnected` — not symmetric. `Disconnected` always writes its `Events` row (`evePendingAlertEmail = 0` when quiet). `Device Down` writes **no row at all** when `devAlertDown = 0`. |
 | `scanPresence` | boolean | `1` | Whether this row asserts the device is *currently online*. `0` means "identity/inventory data, no presence claim" — not "offline". A reservation, a lease record, or a static IPAM entry are typical `0` cases. |
 
 **Missing vs. invalid values — these behave differently, not interchangeably:**