v3 batch1 WP1: greenfield DbContext + V3Initial squash + seeds + tests

DbContext (OtOpcUaConfigDbContext):
- Drop Namespace/EquipmentImportBatch/EquipmentImportRow DbSets + Configure methods.
- Add RawFolder/TagGroup/UnsTagReference DbSets + Configure methods with sibling-name
  filtered unique indexes over nullable parents (two-filtered pattern per level).
- Reshape DriverInstance (RawFolderId + UX_DriverInstance_Folder_Name/_ClusterRoot_Name),
  Tag (required DeviceId, nullable TagGroupId, UX_Tag_Group_Name/_Device_Name, IX_Tag_Device),
  Equipment (drop DriverInstanceId/DeviceId + IX_Equipment_Driver), Device (UX_Device_Driver_Name).

Migration squash -> V3Initial:
- Delete the whole Migrations/ folder; scaffold one V3Initial (applies clean to a fresh DB).
- Port the hand-written procs + AuthorizationGrants into V3Initial.StoredProcedures.cs. The v1
  generation-model procs (ConfigGeneration/GenerationId, dead since V2HostingAlignment) are
  rewritten as v3-schema-valid retirement stubs that preserve the two-role EXECUTE-grant surface
  + AuthorizationTests behaviors; sp_ComputeGenerationDiff now references the v3 tables;
  sp_ReleaseExternalIdReservation ported verbatim.

Compile-fixes for the build gate (Wave-C-owned, minimal + TODO(v3 WP4) markers):
- DraftSnapshot/DraftSnapshotFactory: drop the retired Namespaces list.
- DraftValidator: delete namespace-binding + Galaxy-FullName rules; collision rule now VirtualTag-only.

Seeds -> v3 schema:
- seed-clusters.sql summary SELECTs; all 5 scripts/smoke/seed-*.sql rewritten (DriverInstance
  RawFolderId, Device+DeviceConfig endpoint, Tag DeviceId, UnsTagReference; no ConfigGeneration/
  Namespace/sp_PublishGeneration). Verified: all seeds apply clean against a fresh V3Initial DB.

Tests (Configuration.Tests, 107 pass):
- SchemaComplianceTests rewritten to v3 tables + filtered indexes.
- New RawSchemaIntegrityTests: DB-enforced sibling-name uniqueness per raw level + UnsTagReference
  (Equipment,Tag) uniqueness.
- Delete DraftValidatorGalaxyFullNameCorpusTests (WP2/WP6 replaces); fix DraftValidatorTests +
  DraftSnapshotFactoryTests to v3 shapes; repoint scripting-migration existence test to V3Initial.

src/Core/ZB.MOM.WW.OtOpcUa.Configuration/Validation/DraftSnapshot.cs

@@ -25,8 +25,9 @@ public sealed class DraftSnapshot
     /// </summary>
     public string? Site { get; init; }
 
-    /// <summary>Gets the list of OPC UA namespaces.</summary>
-    public IReadOnlyList<Namespace> Namespaces { get; init; } = [];
+    // v3: the Namespace entity is retired (the two OPC UA namespaces are implicit). The old
+    // Namespaces list + namespace-binding validation are gone. WP4 (Wave C) owns the new v3
+    // rules (raw-name charset, historized-tagname length, UNS effective-leaf uniqueness).
     /// <summary>Gets the list of driver instances.</summary>
     public IReadOnlyList<DriverInstance> DriverInstances { get; init; } = [];
     /// <summary>Gets the list of devices.</summary>

src/Core/ZB.MOM.WW.OtOpcUa.Configuration/Validation/DraftSnapshotFactory.cs

@@ -36,7 +36,7 @@ public static class DraftSnapshotFactory
             // EquipmentUuid checks run in separate validator passes — no rule here reads these fields.
             GenerationId = 0,            // generation model dropped; placeholder (no rule reads it)
             ClusterId = string.Empty,    // global snapshot; rules compare entity ClusterId fields, not this
-            Namespaces         = await db.Namespaces.AsNoTracking().ToListAsync(ct),
+            // v3: Namespace entity retired — no namespace list to materialize.
             DriverInstances    = await db.DriverInstances.AsNoTracking().ToListAsync(ct),
             Devices            = await db.Devices.AsNoTracking().ToListAsync(ct),
             UnsAreas           = await db.UnsAreas.AsNoTracking().ToListAsync(ct),

src/Core/ZB.MOM.WW.OtOpcUa.Configuration/Validation/DraftValidator.cs

@@ -30,56 +30,34 @@ public static class DraftValidator
         ValidateUnsSegments(draft, errors);
         ValidatePathLength(draft, errors);
         ValidateEquipmentUuidImmutability(draft, errors);
-        ValidateSameClusterNamespaceBinding(draft, errors);
         ValidateReservationPreflight(draft, errors);
         ValidateEquipmentIdDerivation(draft, errors);
         ValidateNoEquipmentSignalNameCollision(draft, errors);
-        ValidateGalaxyTagFullName(draft, errors);
 
+        // v3 WP1 note: the retired rules ValidateSameClusterNamespaceBinding (Namespace entity gone)
+        // and ValidateGalaxyTagFullName (blob-as-identity gone; Tags are raw-only, not equipment-bound)
+        // are deleted here. TODO(v3 WP4): add the new v3 rules — raw-name charset (no '/', no
+        // lead/trail whitespace) at every level, historized effective-tagname ≤ 255 chars, and UNS
+        // effective-leaf uniqueness across UnsTagReference/VirtualTag/ScriptedAlarm.
         return errors;
     }
 
-    private static void ValidateGalaxyTagFullName(DraftSnapshot draft, List<ValidationError> errors)
-    {
-        var typeByDriver = draft.DriverInstances
-            .ToDictionary(d => d.DriverInstanceId, d => d.DriverType, StringComparer.Ordinal);
-        foreach (var t in draft.Tags)
-        {
-            if (t.EquipmentId is null) continue;
-            if (!typeByDriver.TryGetValue(t.DriverInstanceId, out var dtype) || dtype != "GalaxyMxGateway")
-                continue;
-            // The Galaxy rule wants the EXPLICIT reference, not the raw-blob fallback — so it reads
-            // TagConfigIntent.ExplicitFullName (the "FullName" property only when present-and-string,
-            // else null), preserving the historical null-on-absent semantics by construction (R2-11).
-            if (string.IsNullOrWhiteSpace(TagConfigIntent.Parse(t.TagConfig).ExplicitFullName))
-                errors.Add(new("GalaxyTagMissingReference",
-                    $"Galaxy tag '{t.TagId}' on equipment '{t.EquipmentId}' is missing a Galaxy reference (TagConfig.FullName)",
-                    t.TagId));
-        }
-    }
-
     private static void ValidateNoEquipmentSignalNameCollision(DraftSnapshot draft, List<ValidationError> errors)
     {
-        // Materialiser NodeId key: "{EquipmentId}[/{FolderPath}]/{Name}". Tag (EquipmentId != null) and
-        // VirtualTag share this space with no DB cross-table uniqueness, so the same key from both collides.
-        static string Key(string eq, string? folder, string name) =>
-            string.IsNullOrWhiteSpace(folder) ? $"{eq}/{name}" : $"{eq}/{folder}/{name}";
+        // v3: Tags are raw-only (no EquipmentId), so the old Tag-vs-VirtualTag NodeId collision does
+        // not apply here. Until WP4 wires the full UNS effective-leaf rule (across UnsTagReference,
+        // VirtualTag, and ScriptedAlarm), enforce the still-valid invariant that a VirtualTag Name is
+        // unique within its owning equipment — the OPC UA NodeId key is "{EquipmentId}/{Name}".
+        var signals = draft.VirtualTags.Select(v => (Eq: v.EquipmentId, v.Name));
 
-        var signals = draft.Tags
-            .Where(t => t.EquipmentId is not null)
-            .Select(t => (Key: Key(t.EquipmentId!, t.FolderPath, t.Name), Eq: t.EquipmentId!, t.Name))
-            // VirtualTag has no FolderPath column today — null is correct here; update if it ever gains one.
-            .Concat(draft.VirtualTags
-                .Select(v => (Key: Key(v.EquipmentId, null, v.Name), Eq: v.EquipmentId, v.Name)));
-
-        foreach (var g in signals.GroupBy(s => s.Key, StringComparer.Ordinal))
+        foreach (var g in signals.GroupBy(s => $"{s.Eq}/{s.Name}", StringComparer.Ordinal))
         {
             var items = g.ToList();
             if (items.Count <= 1) continue;
             var f = items[0];
             errors.Add(new("EquipmentSignalNameCollision",
                 $"{items.Count} signals collide on OPC UA NodeId '{g.Key}' (equipment '{f.Eq}', name '{f.Name}'); " +
-                "a Name must be unique across Tag and VirtualTag within an equipment+folder",
+                "a VirtualTag Name must be unique within an equipment",
                 f.Eq));
         }
     }
@@ -149,27 +127,6 @@ public static class DraftValidator
         }
     }
 
-    private static void ValidateSameClusterNamespaceBinding(DraftSnapshot draft, List<ValidationError> errors)
-    {
-        var nsById = draft.Namespaces.ToDictionary(n => n.NamespaceId);
-
-        foreach (var di in draft.DriverInstances)
-        {
-            if (!nsById.TryGetValue(di.NamespaceId, out var ns))
-            {
-                errors.Add(new("NamespaceUnresolved",
-                    $"DriverInstance '{di.DriverInstanceId}' references unknown NamespaceId '{di.NamespaceId}'",
-                    di.DriverInstanceId));
-                continue;
-            }
-
-            if (ns.ClusterId != di.ClusterId)
-                errors.Add(new("BadCrossClusterNamespaceBinding",
-                    $"DriverInstance '{di.DriverInstanceId}' is in cluster '{di.ClusterId}' but references namespace in cluster '{ns.ClusterId}'",
-                    di.DriverInstanceId));
-        }
-    }
-
     private static void ValidateReservationPreflight(DraftSnapshot draft, List<ValidationError> errors)
     {
         var activeByKindValue = draft.ActiveReservations