Phase 6.2 Stream A — LdapGroupRoleMapping entity + EF migration + CRUD service

Stream A.1-A.2 per docs/v2/implementation/phase-6-2-authorization-runtime.md.
Seed-data migration (A.3) is a separate follow-up once production LDAP group
DNs are finalised; until then CRUD via the Admin UI handles the fleet set up.

Configuration:
- New AdminRole enum {ConfigViewer, ConfigEditor, FleetAdmin} — string-stored.
- New LdapGroupRoleMapping entity with Id (surrogate PK), LdapGroup (512 chars),
  Role (AdminRole enum), ClusterId (nullable, FK to ServerCluster), IsSystemWide,
  CreatedAtUtc, Notes.
- EF config: UX_LdapGroupRoleMapping_Group_Cluster unique index on
  (LdapGroup, ClusterId) + IX_LdapGroupRoleMapping_Group hot-path index on
  LdapGroup for sign-in lookups. Cluster FK cascades on cluster delete.
- Migration 20260419_..._AddLdapGroupRoleMapping generated via `dotnet ef`.

Configuration.Services:
- ILdapGroupRoleMappingService — CRUD surface. Declared as control-plane only
  per decision #150; the OPC UA data-path evaluator must NOT depend on this
  interface (Phase 6.2 compliance check on control/data-plane separation).
  GetByGroupsAsync is the hot-path sign-in lookup.
- LdapGroupRoleMappingService (EF Core impl) enforces the write-time invariant
  "exactly one of (ClusterId populated, IsSystemWide=true)" and surfaces
  InvalidLdapGroupRoleMappingException on violation. Create auto-populates Id
  + CreatedAtUtc when omitted.

Tests (9 new, all pass) in Configuration.Tests:
- Create sets Id + CreatedAtUtc.
- Create rejects empty LdapGroup.
- Create rejects IsSystemWide=true with populated ClusterId.
- Create rejects IsSystemWide=false with null ClusterId.
- GetByGroupsAsync returns matching rows only.
- GetByGroupsAsync with empty input returns empty (no full-table scan).
- ListAllAsync orders by group then cluster.
- Delete removes the target row.
- Delete of unknown id is a no-op.

Microsoft.EntityFrameworkCore.InMemory 10.0.0 added to Configuration.Tests for
the service-level tests (schema-compliance tests still use the live SQL
fixture).

SchemaComplianceTests updated to expect the new LdapGroupRoleMapping table.

Full solution dotnet test: 1051 passing (baseline 906, Phase 6.1 shipped at
1042, Phase 6.2 Stream A adds 9 = 1051). Pre-existing Client.CLI Subscribe
flake unchanged.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/ZB.MOM.WW.OtOpcUa.Configuration/Migrations/20260419131444_AddLdapGroupRoleMapping.cs

@@ -0,0 +1,62 @@
+using System;
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace ZB.MOM.WW.OtOpcUa.Configuration.Migrations
+{
+    /// <inheritdoc />
+    public partial class AddLdapGroupRoleMapping : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.CreateTable(
+                name: "LdapGroupRoleMapping",
+                columns: table => new
+                {
+                    Id = table.Column<Guid>(type: "uniqueidentifier", nullable: false),
+                    LdapGroup = table.Column<string>(type: "nvarchar(512)", maxLength: 512, nullable: false),
+                    Role = table.Column<string>(type: "nvarchar(32)", maxLength: 32, nullable: false),
+                    ClusterId = table.Column<string>(type: "nvarchar(64)", maxLength: 64, nullable: true),
+                    IsSystemWide = table.Column<bool>(type: "bit", nullable: false),
+                    CreatedAtUtc = table.Column<DateTime>(type: "datetime2(3)", nullable: false),
+                    Notes = table.Column<string>(type: "nvarchar(512)", maxLength: 512, nullable: true)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("PK_LdapGroupRoleMapping", x => x.Id);
+                    table.ForeignKey(
+                        name: "FK_LdapGroupRoleMapping_ServerCluster_ClusterId",
+                        column: x => x.ClusterId,
+                        principalTable: "ServerCluster",
+                        principalColumn: "ClusterId",
+                        onDelete: ReferentialAction.Cascade);
+                });
+
+            migrationBuilder.CreateIndex(
+                name: "IX_LdapGroupRoleMapping_ClusterId",
+                table: "LdapGroupRoleMapping",
+                column: "ClusterId");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_LdapGroupRoleMapping_Group",
+                table: "LdapGroupRoleMapping",
+                column: "LdapGroup");
+
+            migrationBuilder.CreateIndex(
+                name: "UX_LdapGroupRoleMapping_Group_Cluster",
+                table: "LdapGroupRoleMapping",
+                columns: new[] { "LdapGroup", "ClusterId" },
+                unique: true,
+                filter: "[ClusterId] IS NOT NULL");
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropTable(
+                name: "LdapGroupRoleMapping");
+        }
+    }
+}