test(e2e): add ListAreaIdsByNamePrefixAsync CLI helper for UI-created area teardown

Adds CliRunner.ListAreaIdsByNamePrefixAsync so Playwright tests can locate
and delete areas they created through the UI without needing the id returned
from a CLI create call. Mirrors ListTemplateIdsByNamePrefixAsync. Round-trip
test verifies create → list-by-prefix → delete against the live cluster.

tests/ZB.MOM.WW.ScadaBridge.CentralUI.PlaywrightTests/Cluster/CliRunner.Helpers.cs

@@ -237,6 +237,52 @@ public static partial class CliRunner
         }
     }
 
+    /// <summary>
+    /// Returns the ids of all areas on <paramref name="siteId"/> whose <c>name</c>
+    /// starts with <paramref name="prefix"/>, via <c>site area list --site-id</c>.
+    /// Used to delete areas a test created through the UI (where the new id is never
+    /// surfaced to the test).
+    ///
+    /// <para>
+    /// Response shape: each element of the returned JSON array carries an integer
+    /// <c>id</c> and a string <c>name</c> (empirically verified against the dev
+    /// cluster — same shapes as the other create/list helpers in this file).
+    /// </para>
+    /// </summary>
+    /// <param name="siteId">Owning site id.</param>
+    /// <param name="prefix">
+    /// Name prefix to filter by (ordinal comparison). Typically the full unique name
+    /// produced by <see cref="UniqueName"/> so exactly one id is returned.
+    /// </param>
+    /// <returns>
+    /// The ids of every area on <paramref name="siteId"/> whose name starts with
+    /// <paramref name="prefix"/>; empty if no areas match.
+    /// </returns>
+    public static async Task<IReadOnlyList<int>> ListAreaIdsByNamePrefixAsync(int siteId, string prefix)
+    {
+        using var doc = await RunJsonAsync(
+            "site", "area", "list",
+            "--site-id", siteId.ToString(System.Globalization.CultureInfo.InvariantCulture));
+
+        var ids = new List<int>();
+        if (doc.RootElement.ValueKind == JsonValueKind.Array)
+        {
+            foreach (var area in doc.RootElement.EnumerateArray())
+            {
+                if (area.TryGetProperty("name", out var name)
+                    && name.ValueKind == JsonValueKind.String
+                    && (name.GetString()?.StartsWith(prefix, StringComparison.Ordinal) ?? false)
+                    && area.TryGetProperty("id", out var id)
+                    && id.TryGetInt32(out var areaId))
+                {
+                    ids.Add(areaId);
+                }
+            }
+        }
+
+        return ids;
+    }
+
     /// <summary>
     /// Best-effort delete of a site via <c>site delete</c> for teardown; swallows
     /// any failure.

tests/ZB.MOM.WW.ScadaBridge.CentralUI.PlaywrightTests/Cluster/CliRunnerHelpersTests.cs

@@ -84,4 +84,31 @@ public class CliRunnerHelpersTests
             await CliRunner.DeleteApiMethodAsync(id);
         }
     }
+
+    /// <summary>
+    /// A freshly created area is discoverable by name prefix via
+    /// <see cref="CliRunner.ListAreaIdsByNamePrefixAsync"/>, confirming the round-trip
+    /// used by UI tests that need to tear down areas whose ids are never surfaced.
+    /// Exercises <see cref="CliRunner.CreateAreaAsync"/>,
+    /// <see cref="CliRunner.ListAreaIdsByNamePrefixAsync"/>, and
+    /// <see cref="CliRunner.DeleteAreaAsync"/>.
+    /// </summary>
+    [SkippableFact]
+    public async Task ListAreaIdsByNamePrefix_FindsCreatedArea()
+    {
+        Skip.IfNot(await ClusterAvailability.IsAvailableAsync(), ClusterAvailability.SkipReason);
+
+        var siteId = await CliRunner.ResolveSiteIdAsync("site-a");
+        var name = CliRunner.UniqueName("listarea");
+        var areaId = await CliRunner.CreateAreaAsync(siteId, name);
+        try
+        {
+            var ids = await CliRunner.ListAreaIdsByNamePrefixAsync(siteId, name);
+            Assert.Contains(areaId, ids);
+        }
+        finally
+        {
+            await CliRunner.DeleteAreaAsync(areaId);
+        }
+    }
 }