Auto: s7-c3 — per-tag scan group / publish rate

Closes #296

src/ZB.MOM.WW.OtOpcUa.Driver.S7/S7DriverFactoryExtensions.cs

@@ -34,6 +34,22 @@ public static class S7DriverFactoryExtensions
             throw new InvalidOperationException(
                 $"S7 driver config for '{driverInstanceId}' missing required Host");
 
+        // PR-S7-C3 — translate ScanGroupIntervalsMs (string -> int ms) into the runtime
+        // string -> TimeSpan map. Skip any entry with a non-positive value rather than
+        // throwing, so a config typo (e.g. 0 ms) degrades to "fall back to default
+        // publishing interval" instead of breaking the whole driver init.
+        IReadOnlyDictionary<string, TimeSpan>? scanGroupMap = null;
+        if (dto.ScanGroupIntervalsMs is { Count: > 0 })
+        {
+            var built = new Dictionary<string, TimeSpan>(StringComparer.OrdinalIgnoreCase);
+            foreach (var kvp in dto.ScanGroupIntervalsMs)
+            {
+                if (string.IsNullOrWhiteSpace(kvp.Key) || kvp.Value <= 0) continue;
+                built[kvp.Key] = TimeSpan.FromMilliseconds(kvp.Value);
+            }
+            if (built.Count > 0) scanGroupMap = built;
+        }
+
         var options = new S7DriverOptions
         {
             Host = dto.Host!,
@@ -57,6 +73,7 @@ public static class S7DriverFactoryExtensions
                 fallback: TsapMode.Auto),
             LocalTsap = dto.LocalTsap,
             RemoteTsap = dto.RemoteTsap,
+            ScanGroupIntervals = scanGroupMap,
         };
 
         return new S7Driver(options, driverInstanceId);
@@ -72,7 +89,8 @@ public static class S7DriverFactoryExtensions
                 tagName: t.Name),
             Writable: t.Writable ?? true,
             StringLength: t.StringLength ?? 254,
-            WriteIdempotent: t.WriteIdempotent ?? false);
+            WriteIdempotent: t.WriteIdempotent ?? false,
+            ScanGroup: string.IsNullOrWhiteSpace(t.ScanGroup) ? null : t.ScanGroup);
 
     private static T ParseEnum<T>(string? raw, string driverInstanceId, string field,
         string? tagName = null, T? fallback = null) where T : struct, Enum
@@ -122,6 +140,15 @@ public static class S7DriverFactoryExtensions
 
         /// <summary>Optional 16-bit remote TSAP override. Required (with <see cref="LocalTsap"/>) when <c>TsapMode = Other</c>.</summary>
         public ushort? RemoteTsap { get; init; }
+
+        /// <summary>
+        ///     PR-S7-C3 — optional scan-group → publishing-interval (ms) map. Tags carrying
+        ///     a matching <see cref="S7TagDto.ScanGroup"/> string poll at the configured
+        ///     rate; tags with no group, or with a group not present here, fall back to
+        ///     the subscription default. Group names are matched case-insensitively. See
+        ///     <c>docs/v2/s7.md</c> "Per-tag scan groups" section.
+        /// </summary>
+        public Dictionary<string, int>? ScanGroupIntervalsMs { get; init; }
     }
 
     internal sealed class S7TagDto
@@ -132,6 +159,14 @@ public static class S7DriverFactoryExtensions
         public bool? Writable { get; init; }
         public int? StringLength { get; init; }
         public bool? WriteIdempotent { get; init; }
+
+        /// <summary>
+        ///     PR-S7-C3 — optional scan-group identifier. Resolved against
+        ///     <see cref="S7DriverConfigDto.ScanGroupIntervalsMs"/> at subscribe time.
+        ///     Null / empty = no group (legacy behaviour, falls back to subscription
+        ///     default publishing interval).
+        /// </summary>
+        public string? ScanGroup { get; init; }
     }
 
     internal sealed class S7ProbeDto