perf(search): prefix-by-default Deployments and config-audit search; bounded Contains opt-in (ScadaBridge#50)

Deployments free-text search and the config-audit EntityName filter no longer
emit LIKE '%term%' by default. Prefix (LIKE 'term%') is the default; substring
is an explicit opt-in (DeploymentSearchMode.Contains / entityNameContains)
always bounded by a DeployedAt/Timestamp window (explicit, else 30 days).
Migration PrefixSearchIndexes adds DeployedBy, RevisionHash and EntityName
indexes. Deployments page gains a 'Match anywhere' checkbox.

Claude-Session: https://claude.ai/code/session_01GT67AEHd2Acv1YPwGfXEoV

src/ZB.MOM.WW.ScadaBridge.ConfigurationDatabase/Repositories/CentralUiRepository.cs

@@ -127,33 +127,12 @@ public class CentralUiRepository : ICentralUiRepository
         Guid? bundleImportId = null,
         int page = 1,
         int pageSize = 50,
-        CancellationToken cancellationToken = default)
+        CancellationToken cancellationToken = default,
+        bool entityNameContains = false)
     {
-        var query = _context.AuditLogEntries.AsNoTracking().AsQueryable();
-
-        if (!string.IsNullOrWhiteSpace(user))
-            query = query.Where(a => a.User == user);
-
-        if (!string.IsNullOrWhiteSpace(entityType))
-            query = query.Where(a => a.EntityType == entityType);
-
-        if (!string.IsNullOrWhiteSpace(action))
-            query = query.Where(a => a.Action == action);
-
-        if (from.HasValue)
-            query = query.Where(a => a.Timestamp >= from.Value);
-
-        if (to.HasValue)
-            query = query.Where(a => a.Timestamp <= to.Value);
-
-        if (!string.IsNullOrWhiteSpace(entityId))
-            query = query.Where(a => a.EntityId == entityId);
-
-        if (!string.IsNullOrWhiteSpace(entityName))
-            query = query.Where(a => a.EntityName.Contains(entityName));
-
-        if (bundleImportId is Guid bundleId)
-            query = query.Where(a => a.BundleImportId == bundleId);
+        var query = BuildAuditLogQuery(
+            user, entityType, action, from, to, entityId, entityName, bundleImportId,
+            entityNameContains, DateTimeOffset.UtcNow);
 
         var totalCount = await query.CountAsync(cancellationToken);
 
@@ -169,6 +148,51 @@ public class CentralUiRepository : ICentralUiRepository
         return (entries, totalCount);
     }
 
+    /// <summary>Default window for an opt-in entity-name substring search with no explicit <c>from</c>.</summary>
+    internal static readonly TimeSpan EntityNameContainsDefaultWindow = TimeSpan.FromDays(30);
+
+    internal IQueryable<AuditLogEntry> BuildAuditLogQuery(
+        string? user, string? entityType, string? action, DateTimeOffset? from, DateTimeOffset? to,
+        string? entityId, string? entityName, Guid? bundleImportId, bool entityNameContains, DateTimeOffset nowUtc)
+    {
+        var query = _context.AuditLogEntries.AsNoTracking().AsQueryable();
+
+        if (!string.IsNullOrWhiteSpace(user))
+            query = query.Where(a => a.User == user);
+
+        if (!string.IsNullOrWhiteSpace(entityType))
+            query = query.Where(a => a.EntityType == entityType);
+
+        if (!string.IsNullOrWhiteSpace(action))
+            query = query.Where(a => a.Action == action);
+
+        // A substring name search scans, so it is never unbounded: without an explicit
+        // `from` it is limited to the last EntityNameContainsDefaultWindow (ScadaBridge#50).
+        var contains = entityNameContains && !string.IsNullOrWhiteSpace(entityName);
+        var effectiveFrom = from ?? (contains ? nowUtc - EntityNameContainsDefaultWindow : (DateTimeOffset?)null);
+        if (effectiveFrom.HasValue)
+        {
+            var lowerBound = effectiveFrom.Value;
+            query = query.Where(a => a.Timestamp >= lowerBound);
+        }
+
+        if (to.HasValue)
+            query = query.Where(a => a.Timestamp <= to.Value);
+
+        if (!string.IsNullOrWhiteSpace(entityId))
+            query = query.Where(a => a.EntityId == entityId);
+
+        if (!string.IsNullOrWhiteSpace(entityName))
+            query = contains
+                ? query.Where(a => a.EntityName.Contains(entityName))
+                : query.Where(a => a.EntityName.StartsWith(entityName));
+
+        if (bundleImportId is Guid bundleId)
+            query = query.Where(a => a.BundleImportId == bundleId);
+
+        return query;
+    }
+
     /// <inheritdoc />
     public async Task<int> SaveChangesAsync(CancellationToken cancellationToken = default)
     {

src/ZB.MOM.WW.ScadaBridge.ConfigurationDatabase/Repositories/DeploymentManagerRepository.cs

@@ -57,7 +57,7 @@ public class DeploymentManagerRepository : IDeploymentManagerRepository
     /// status-count aggregation needs every status of the otherwise-identical set.
     /// </param>
     /// <returns>The composed, unordered, untracked query.</returns>
-    private IQueryable<DeploymentInstanceJoin> BuildListQuery(DeploymentListFilter filter, bool applyStatus)
+    internal IQueryable<DeploymentInstanceJoin> BuildListQuery(DeploymentListFilter filter, bool applyStatus)
     {
         ArgumentNullException.ThrowIfNull(filter);
 
@@ -93,16 +93,26 @@ public class DeploymentManagerRepository : IDeploymentManagerRepository
             query = query.Where(r => scope.Contains(r.SiteId));
         }
 
+        if (filter.EffectiveDeployedFrom(DateTimeOffset.UtcNow) is { } from)
+            query = query.Where(r => r.DeployedAt >= from);
+
         if (filter.NormalizedSearch is { } search)
         {
-            // Substring match across the four identifiers a deployment is findable
-            // by. Translated to LIKE '%term%' by both providers; case-insensitivity
-            // is the database collation's (SQL Server default CI, SQLite ASCII LIKE).
-            query = query.Where(r =>
-                r.InstanceUniqueName.Contains(search)
-                || r.DeploymentId.Contains(search)
-                || r.DeployedBy.Contains(search)
-                || (r.RevisionHash != null && r.RevisionHash.Contains(search)));
+            // Default: PREFIX match across the four identifiers a deployment is findable
+            // by (LIKE 'term%', index-seekable; case-insensitivity is the database
+            // collation's). Contains is the explicit opt-in scan (LIKE '%term%') and is
+            // always bounded by the DeployedAt window applied above (ScadaBridge#50).
+            query = filter.SearchMode == DeploymentSearchMode.Contains
+                ? query.Where(r =>
+                    r.InstanceUniqueName.Contains(search)
+                    || r.DeploymentId.Contains(search)
+                    || r.DeployedBy.Contains(search)
+                    || (r.RevisionHash != null && r.RevisionHash.Contains(search)))
+                : query.Where(r =>
+                    r.InstanceUniqueName.StartsWith(search)
+                    || r.DeploymentId.StartsWith(search)
+                    || r.DeployedBy.StartsWith(search)
+                    || (r.RevisionHash != null && r.RevisionHash.StartsWith(search)));
         }
 
         return query;
@@ -873,7 +883,7 @@ public class DeploymentManagerRepository : IDeploymentManagerRepository
     /// lockstep. Not a public contract — <see cref="DeploymentListRow"/> is what
     /// leaves this class.
     /// </summary>
-    private sealed class DeploymentInstanceJoin
+    internal sealed class DeploymentInstanceJoin
     {
         /// <summary>Deployment record primary key.</summary>
         public int Id { get; init; }