v3 batch1 contracts: RawPaths identity helper + reshaped greenfield entities

Shared-type foundation for Batch 1 fan-out (coordinator contracts commit):
- New Commons/Types/RawPaths.cs — the v3 identity authority (Build/Combine/
  Split/Leaf/TryParent/ValidateSegment, ordinal comparer).
- New entities RawFolder, TagGroup, UnsTagReference.
- Reshape DriverInstance (drop NamespaceId, add nullable RawFolderId),
  Tag (require DeviceId, add nullable TagGroupId, drop DriverInstanceId/
  EquipmentId/FolderPath, keep WriteIdempotent), Equipment (drop
  DriverInstanceId/DeviceId), Device (doc: now universal), ServerCluster
  (nav Namespaces -> RawFolders).
- Delete Namespace, EquipmentImportBatch(+Row), NamespaceKind enum.
- DriverTypeMetadata: drop AllowedNamespaceKinds + NamespaceKindCompatibility.

Solution is intentionally red below the foundation projects until Wave C
integrates. Commons + Core.Abstractions compile green.

src/Core/ZB.MOM.WW.OtOpcUa.Core.Abstractions/DriverTypeRegistry.cs

@@ -84,7 +84,6 @@ public sealed class DriverTypeRegistry
 
 /// <summary>Per-driver-type metadata used by the Core, validator, and Admin UI.</summary>
 /// <param name="TypeName">Driver type name (matches <c>DriverInstance.DriverType</c> column values).</param>
-/// <param name="AllowedNamespaceKinds">Which namespace kinds this driver type may be bound to.</param>
 /// <param name="DriverConfigJsonSchema">JSON Schema (Draft 2020-12) the driver's <c>DriverConfig</c> column must validate against.</param>
 /// <param name="DeviceConfigJsonSchema">JSON Schema for <c>DeviceConfig</c> (multi-device drivers); null if the driver has no device layer.</param>
 /// <param name="TagConfigJsonSchema">JSON Schema for <c>TagConfig</c>; required for every driver since every driver has tags.</param>
@@ -95,24 +94,11 @@ public sealed class DriverTypeRegistry
 ///     hybrid-formula constants, and whether process-level <c>MemoryRecycle</c> / scheduled-
 ///     recycle protections apply (Tier C only). Every registered driver type must declare one.
 /// </param>
+// v3: AllowedNamespaceKinds retired with the Namespace entity — the two OPC UA namespaces (Raw/UNS)
+// are implicit, so a driver type no longer declares a namespace-kind compatibility bitmask.
 public sealed record DriverTypeMetadata(
     string TypeName,
-    NamespaceKindCompatibility AllowedNamespaceKinds,
     string DriverConfigJsonSchema,
     string? DeviceConfigJsonSchema,
     string TagConfigJsonSchema,
     DriverTier Tier);
-
-/// <summary>Bitmask of namespace kinds a driver type may populate.</summary>
-[Flags]
-public enum NamespaceKindCompatibility
-{
-    /// <summary>Driver does not populate any namespace (invalid; should never appear in registry).</summary>
-    None = 0,
-
-    /// <summary>Driver may populate Equipment-kind namespaces (UNS path, Equipment rows).</summary>
-    Equipment = 1,
-
-    /// <summary>Driver may populate the future Simulated namespace (replay driver — not in v2.0).</summary>
-    Simulated = 4,
-}