fix(code-review): resolve Batch 2 open findings (AbCip, AbLegacy, Galaxy, FOCAS)

- Driver.AbCip.Contracts-001: parse 'writable' from TagConfig JSON (default true) instead of hardcoding
- Driver.AbCip.Contracts-002/-003: Dt type comment; drop dead [Display]/[Range] annotations
- Driver.AbCip.Contracts-004: dedicated AbCipEquipmentTagParser test class (+15)
- Driver.AbCip-017: document Tick severity Low-fallback on Bad severity read
- Driver.AbLegacy.Contracts-002/-003/-004: isArray-scalar remarks (+tests), MaxTagBytes/ForFamily docs
- Driver.Galaxy.Browser-003 + Driver.Galaxy.Contracts-003: extract ResolveApiKey -> GalaxySecretRef (dedup)
- Driver.Galaxy-019: cache buffered-interval only on Ok + ILogger warnings + ClassifyIntervalReply (+tests)
- Driver.FOCAS.Contracts-002: thread WriteIdempotent through DiscoverAsync (+test)

src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.AbCip.Contracts/AbCipDataType.cs

@@ -25,7 +25,9 @@ public enum AbCipDataType
     Real,   // 32-bit IEEE-754
     LReal,  // 64-bit IEEE-754
     String, // Logix STRING (DINT Length + SINT[82] DATA — flattened to .NET string by libplctag)
-    Dt,     // Date/Time — Logix DT == DINT representing seconds-since-epoch per Rockwell conventions
+    Dt,     // Logix DATE (0xCD — 4-byte unsigned days since 1984-01-01) or DATE_AND_TIME / DT
+            // (0xCF — 8-byte unsigned microseconds since 1970-01-01). The driver reads 4 bytes
+            // via GetInt32; DATE decodes correctly, DATE_AND_TIME is truncated to the low 4 bytes.
     /// <summary>
     ///     UDT / Predefined Structure (Timer / Counter / Control / Message / Axis). Shape is
     ///     resolved at discovery time; reads + writes fan out to member Variables unless the

src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.AbCip.Contracts/AbCipDriverOptions.cs

@@ -1,5 +1,3 @@
-using System.ComponentModel.DataAnnotations;
-
 namespace ZB.MOM.WW.OtOpcUa.Driver.AbCip;
 
 /// <summary>
@@ -81,8 +79,7 @@ public sealed class AbCipDriverOptions
     ///     Timeout for the AdminUI Test Connect probe, in seconds. The AdminUI clamps to a
     ///     60s server-side maximum; this default is what the form pre-fills for new instances.
     /// </summary>
-    [Display(Name = "Probe timeout (seconds)", Description = "Connection test timeout. Default 5s.", GroupName = "Diagnostics")]
-    [Range(1, 60)]
+    /// <remarks>Valid range: 1–60 seconds; the AdminUI clamps to 60s server-side.</remarks>
     public int ProbeTimeoutSeconds { get; init; } = 5;
 }
 

src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.AbCip.Contracts/AbCipEquipmentTagParser.cs

@@ -13,10 +13,11 @@ public static class AbCipEquipmentTagParser
     /// <param name="def">The transient definition when parsing succeeds.</param>
     /// <returns><see langword="true"/> when <paramref name="reference"/> is an AbCip TagConfig object.</returns>
     /// <remarks>
-    ///     The produced <see cref="AbCipTagDefinition.Writable"/> is always <c>true</c>: the
-    ///     TagConfig JSON format for equipment tags does not carry a writability field, so the
-    ///     PLC's ExternalAccess attribute is the effective write gate. Operators who need a
-    ///     read-only OPC UA surface must rely on the PLC's ExternalAccess rejecting the write.
+    ///     <see cref="AbCipTagDefinition.Writable"/> is read from the optional <c>"writable"</c>
+    ///     boolean field in the TagConfig JSON; it defaults to <c>true</c> when the field is absent,
+    ///     matching the record's documented default and the behaviour of pre-declared tags. Operators
+    ///     who need a read-only OPC UA surface can author <c>"writable":false</c> in the TagConfig;
+    ///     the PLC's ExternalAccess attribute remains the effective write gate at the wire level.
     /// </remarks>
     public static bool TryParse(string reference, out AbCipTagDefinition def)
     {
@@ -36,6 +37,11 @@ public static class AbCipEquipmentTagParser
             if (string.IsNullOrWhiteSpace(tagPath)) return false;
 
             var deviceHostAddress = ReadString(root, "deviceHostAddress");
+            // A "dataType":"Structure" input is accepted and produces a Structure-typed definition
+            // with Members:null. The driver treats this as a black-box dotted-path read: libplctag
+            // resolves the full tag path (e.g. "Motor.Speed") without enumerating UDT members.
+            // The address space emits a placeholder String variable; UDT member declarations are
+            // not supported in the equipment-tag flow.
             var dataType = ReadEnum(root, "dataType", AbCipDataType.DInt);
             // Review I-1 — an equipment tag is an ARRAY ⟺ isArray:true AND arrayLength >= 1. A
             // 1-element array (isArray:true, arrayLength:1) is a VALID 1-element array — the
@@ -43,9 +49,12 @@ public static class AbCipEquipmentTagParser
             // scalar. ElementCount can't carry the signal (a scalar and a 1-element array both
             // have a count of 1), so the explicit IsArray flag does.
             var (isArray, elementCount) = ReadArrayShape(root);
+            // "writable" defaults to true when absent — matches AbCipTagDefinition.Writable default.
+            var writable = !root.TryGetProperty("writable", out var writableEl)
+                           || writableEl.ValueKind != JsonValueKind.False;
             def = new AbCipTagDefinition(
                 Name: reference, DeviceHostAddress: deviceHostAddress, TagPath: tagPath,
-                DataType: dataType, Writable: true, ElementCount: elementCount, IsArray: isArray);
+                DataType: dataType, Writable: writable, ElementCount: elementCount, IsArray: isArray);
             return true;
         }
         catch (JsonException) { return false; }