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/Configurations/DeploymentConfiguration.cs

@@ -40,6 +40,11 @@ public class DeploymentRecordConfiguration : IEntityTypeConfiguration<Deployment
         builder.HasIndex(d => d.DeploymentId).IsUnique();
         builder.HasIndex(d => d.InstanceId);
 
+        // Prefix-search legs of the Deployments page free-text search (ScadaBridge#50):
+        // DeploymentId and Instance.UniqueName are already uniquely indexed.
+        builder.HasIndex(d => d.DeployedBy).HasDatabaseName("IX_DeploymentRecords_DeployedBy");
+        builder.HasIndex(d => d.RevisionHash).HasDatabaseName("IX_DeploymentRecords_RevisionHash");
+
         // Deployment-list sort key. Every list read orders DeployedAt DESC, Id DESC
         // (DeploymentManagerRepository.QueryDeploymentListPageAsync, which register
         // row 37 made the single paged read behind BOTH the Central UI page and the