docs(probe): close superseded unblock bullet, hedge the summary, evidence gobject_id, ack-caveat in RPC docs

docs/Grpc.md

@@ -92,6 +92,8 @@ An accepted gRPC command payload can still be too large for the worker pipe: the
 
 `AcknowledgeAlarm` is a unary, **session-less** RPC that acknowledges a single alarm. The handler validates `alarm_full_reference` inline (it does not run through `MxAccessGrpcRequestValidator`) and delegates to `IGatewayAlarmService.AcknowledgeAsync`. The always-on `GatewayAlarmMonitor` routes the ack over its own gateway-managed worker session — clients no longer open a session to acknowledge an alarm. A reference that parses as a canonical GUID forwards to `AcknowledgeAlarmCommand`; a `Provider!Group.Tag` reference forwards to `AcknowledgeAlarmByNameCommand`.
 
+An `OK` response means the alarm provider accepted the acknowledgement, not that it applied it: the gateway forwards the ack and reports what the provider returned, in keeping with the parity rule. On galaxies whose alarmed attributes carry a non-free-access security classification the by-name ack is accepted and inert — the underlying `AlarmAckByName` conveys an operator name rather than an authenticated identity — so a client that needs to confirm an acknowledgement should watch for the resulting transition on `StreamAlarms` instead of treating `OK` as proof. See [Alarm Probe Findings](./AlarmProbeFindings.md).
+
 ### `StreamAlarms`
 
 `StreamAlarms` is a server-streaming, **session-less** RPC that attaches to the gateway's central alarm feed. The handler delegates to `IGatewayAlarmService.StreamAsync`. The stream opens with a `provider_status` and a `snapshot_status` `AlarmFeedMessage` (the current provider mode and snapshot-completeness verdict), then one `AlarmFeedMessage` carrying an `active_alarm` per currently-active alarm (the ConditionRefresh snapshot), then a single `snapshot_complete`, then a `transition` for every subsequent raise / acknowledge / clear — interleaved with a further `provider_status` on each failover/failback and a further `snapshot_status` on each change of the truncation verdict. It is served by the always-on `GatewayAlarmMonitor`, which owns a single gateway-managed worker session and fans out to every attached client — clients no longer open a session of their own. `alarm_filter_prefix`, when set, scopes the stream to a sub-tree.