fix(mtconnect): on a changed alarm set forget only the conditions that left (#641)

The driver cleared its whole "last told" record whenever the subscribed alarm
set changed, assuming the rebuild that accompanies an alarm-bearing delta had
reset every condition node. The server now carries each surviving native
condition's state (acknowledgement included) across the rebuild, so re-raising a
survivor would un-acknowledge it. Only entries that left the set are dropped; a
condition that comes back later is told again onto its fresh node.

Claude-Session: https://claude.ai/code/session_01Ef2ozxS7QPanGT8uoATbTe

docs/drivers/MTConnect.md

@@ -462,11 +462,12 @@ and records a state only when an alarm handler was attached to receive it. Conse
   condition the driver owns `BadNoCommunication` on the connectivity edge (#477) and keeps its Active
   state; the reconnect edge re-annotates Good, after which the driver re-asserts any still-`Unavailable`
   condition's Bad quality on its re-subscribe.
-- A re-subscribe with a **changed** alarm set clears the whole told record: only an alarm-bearing raw-tag
-  delta changes the set, the server applies that as a full rebuild, and a rebuild recreates every
-  condition node inactive — so every active condition is re-asserted onto its new node. The **same** set
-  (a reconnect) keeps the record. (A rebuild that leaves this driver's alarm set unchanged triggers no
-  re-subscribe; that is a host-wide gap shared with every native source.)
+- A re-subscribe with a **changed** alarm set drops the told record of only the conditions that **left**
+  the set. The server carries every native condition's state (acknowledgement included) across a full
+  rebuild itself (Gitea #641 — see `docs/AlarmTracking.md`), so re-raising a surviving condition would
+  only un-acknowledge it; a condition that left and later comes back was materialised fresh and is told
+  again. The **same** set (a reconnect) keeps the whole record. A rebuild that leaves the alarm set
+  unchanged triggers no re-subscribe, and needs none — the server-side carry-over covers it.
 - An alarm-only driver (no value tags) still runs the `/sample` pump.
 
 **EVENT controlled vocabularies as OPC UA enumerations — won't fix.** EVENT values (`Execution`,