feat(historian): typed HistorianValue contracts, IHistorianDataUpdater, IHistorianBackendProvider (no behaviour change)

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

src/Server/ZB.MOM.WW.OtOpcUa.Runtime/Historian/ContinuousHistorizationRecorder.cs

@@ -524,7 +524,8 @@ public sealed class ContinuousHistorizationRecorder : ReceiveActor, IWithTimers
                 + "resuming value capture.");
         }
 
-        if (!TryCoerceToDouble(msg.Value, out double numeric))
+        if (!(HistorianValue.TryFromObject(msg.Value, out HistorianValue historianValue)
+              && historianValue.TryGetDouble(out double numeric)))
         {
             // The SQL analog live-value path is numeric-only — drop non-coercible values (string/null/
             // reference) and meter the drop. No value content is logged.
@@ -548,8 +549,8 @@ public sealed class ContinuousHistorizationRecorder : ReceiveActor, IWithTimers
             entries.Add(new HistorizationOutboxEntry(
                 Guid.NewGuid(),
                 historianName,
-                numeric,
-                GoodQuality,
+                HistorianValue.FromDouble(numeric),
+                0u, // Good
                 timestampUtc));
         }
     }
@@ -689,7 +690,7 @@ public sealed class ContinuousHistorizationRecorder : ReceiveActor, IWithTimers
                 .Select(g => (
                     Key: g.Key,
                     Values: (IReadOnlyList<HistorizationValue>)g
-                        .Select(e => new HistorizationValue(e.TimestampUtc, e.NumericValue, e.Quality))
+                        .Select(e => new HistorizationValue(e.TimestampUtc, e.Value, e.StatusCode))
                         .ToList()))
                 .ToList();
 
@@ -879,24 +880,4 @@ public sealed class ContinuousHistorizationRecorder : ReceiveActor, IWithTimers
     }
 
     private static TimeSpan Min(TimeSpan a, TimeSpan b) => a < b ? a : b;
-
-    private static bool TryCoerceToDouble(object? value, out double result)
-    {
-        switch (value)
-        {
-            case double d: result = d; return true;
-            case float f: result = f; return true;
-            case int i: result = i; return true;
-            case long l: result = l; return true;
-            case short s: result = s; return true;
-            case ushort us: result = us; return true;
-            case uint ui: result = ui; return true;
-            case ulong ul: result = ul; return true;
-            case byte b: result = b; return true;
-            case sbyte sb: result = sb; return true;
-            case decimal dec: result = (double)dec; return true;
-            case bool bo: result = bo ? 1d : 0d; return true;   // Boolean historizes as Int1 (1/0).
-            default: result = 0d; return false;                 // string / null / DateTime / reference -> dropped.
-        }
-    }
 }

src/Server/ZB.MOM.WW.OtOpcUa.Runtime/Historian/IHistorianBackendProvider.cs

@@ -0,0 +1,42 @@
+using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
+using ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian;
+
+namespace ZB.MOM.WW.OtOpcUa.Runtime.Historian;
+
+/// <summary>
+///     Builds the historian seams (read, live-value write, alarm write, provisioning, optional update)
+///     for one historian backend. The Host selects a provider by <see cref="Name"/>.
+/// </summary>
+public interface IHistorianBackendProvider
+{
+    /// <summary>Backend name, e.g. "Gateway" or "SqlServer".</summary>
+    string Name { get; }
+
+    /// <summary>The value kinds this backend can store; the recorder drops other kinds at capture.</summary>
+    IReadOnlySet<HistorianValueKind> SupportedKinds { get; }
+
+    /// <summary>Creates the HistoryRead data source.</summary>
+    /// <param name="sp">Service provider.</param>
+    /// <returns>The data source.</returns>
+    IHistorianDataSource CreateDataSource(IServiceProvider sp);
+
+    /// <summary>Creates the continuous-historization live-value writer.</summary>
+    /// <param name="sp">Service provider.</param>
+    /// <returns>The value writer.</returns>
+    IHistorianValueWriter CreateValueWriter(IServiceProvider sp);
+
+    /// <summary>Creates the alarm-history writer.</summary>
+    /// <param name="sp">Service provider.</param>
+    /// <returns>The alarm writer.</returns>
+    IAlarmHistorianWriter CreateAlarmWriter(IServiceProvider sp);
+
+    /// <summary>Creates the tag auto-provisioning hook.</summary>
+    /// <param name="sp">Service provider.</param>
+    /// <returns>The provisioning hook.</returns>
+    IHistorianProvisioning CreateProvisioning(IServiceProvider sp);
+
+    /// <summary>Creates the HistoryUpdate capability.</summary>
+    /// <param name="sp">Service provider.</param>
+    /// <returns>The updater, or <c>null</c> when the backend does not support HistoryUpdate.</returns>
+    IHistorianDataUpdater? CreateUpdater(IServiceProvider sp);
+}