fix(modbus): refusals are per-tag Bad, batch health, generation-stamped lifecycle, write status mapping

H4: exception 01/02/03 (and undecodable data) are device refusals - per-tag
Bad with a once-per-tag Warning, no Degraded, and they advance
LastSuccessfulRead (the device answered), so an all-refused driver no longer
trips the 90 s watchdog. 04/05/06 still degrade (answered); 0A/0B degrade
without advancing. Health is one worst-wins write per batch instead of
last-writer-wins per tag. A comms failure on one unit fails the rest of
that unit's batch fast; an unreachable endpoint fails the whole batch fast.
H7: write transport failures map to BadCommunicationError, value overflow and
array length mismatch to BadOutOfRange, conversion failures to
BadTypeMismatch; writes report write-side health (a good write or a refusal
clears a write-side Degraded; a good read does not).
Lifecycle: every health write and the transport/table publish carry a
generation; a superseded init releases its transport and publishes nothing,
a read straddling a re-init cannot degrade the new transport, and the
shutdown's final write cannot clobber a newer init. The tag table is
build-and-swapped (re-init no longer merges into the old table). Teardown
joins the probe/re-probe loops (bounded); a probe answer advances
LastSuccessfulRead and an exception PDU from the device counts as Running.
Transports latch dispose atomically and never reconnect after it.

Refs #741
Claude-Session: https://claude.ai/code/session_01Ub9hGmYLQvn9XETzw7CMsT

src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Modbus/ModbusWriteRefusedException.cs

@@ -0,0 +1,21 @@
+namespace ZB.MOM.WW.OtOpcUa.Driver.Modbus;
+
+/// <summary>
+///     The driver refused a write BEFORE anything reached the wire (wrong array length, a payload over
+///     <c>MaxRegistersPerWrite</c>, an unsupported shape). Carries the OPC UA status the write returns;
+///     it never touches driver health — nothing was sent.
+/// </summary>
+public sealed class ModbusWriteRefusedException : Exception
+{
+    /// <summary>Initializes a new instance of the <see cref="ModbusWriteRefusedException"/> class.</summary>
+    /// <param name="statusCode">The OPC UA status the write returns.</param>
+    /// <param name="message">A human-readable description.</param>
+    public ModbusWriteRefusedException(uint statusCode, string message)
+        : base(message)
+    {
+        StatusCode = statusCode;
+    }
+
+    /// <summary>Gets the OPC UA status the write returns.</summary>
+    public uint StatusCode { get; }
+}