chore(clients/dotnet): bump Contracts + Client 0.2.1 -> 0.3.0 for publish (#214)

0.2.1 on the feed predates the 488649c AcknowledgeAlarmRequest
operator_password/operator_domain fields; 0.3.0 ships them so OtOpcUa can
adopt operator-authenticated alarm ack (lmxopcua#749).

docs/ClientPackaging.md

@@ -128,6 +128,15 @@ confirmed present through the Gitea package API after the push, and
 `go list -m` resolves the Go tag. These are the numbers a future release
 bumps off.
 
+On 2026-11-06 (#214) the .NET pair alone moved to **0.3.0**: `nuget`
+`ZB.MOM.WW.MxGateway.Contracts` **0.3.0** and `ZB.MOM.WW.MxGateway.Client`
+**0.3.0**. The release carries the additive `AcknowledgeAlarmRequest`
+`operator_password` / `operator_domain` fields from `488649c`. The feed's
+0.2.1 predates them, so OtOpcUa could not consume operator-authenticated
+alarm ack. The minor bump marks a new wire field. The Python, Rust, Java and
+Go clients were not republished in that release, and their manifests were
+left alone.
+
 **The published pypi `0.2.0` artifact has a broken `connect()` (CLI-46).**
 Its `connect()` built the `grpc.aio` channel inside `asyncio.to_thread`, and
 a `grpc.aio` channel binds to the event loop current on the *constructing*