test(centralui): e2e execution-tree node detail modal + docs

docs/requirements/Component-AuditLog.md

@@ -428,6 +428,9 @@ global value in v1; per-channel overrides are deferred to v1.x.
   hosts the Audit Log page (filter bar, results grid, drilldown drawer,
   server-side CSV export). Drill-in links appear on Notifications, Site Calls,
   External Systems, Inbound API key, Sites, and Instances detail pages.
+  Double-clicking a node on the execution-tree page opens a detail modal
+  listing that execution's audit rows, with click-through to each row's full
+  detail view.
 - **[Health Monitoring (#11)](Component-HealthMonitoring.md)** — three new
   tiles (Volume, Error rate, Backlog) plus new health metrics:
   `SiteAuditBacklog`, `SiteAuditWriteFailures`, `SiteAuditTelemetryStalled`,

tests/ScadaLink.CentralUI.PlaywrightTests/Audit/AuditLogPageTests.cs

@@ -516,6 +516,110 @@ public class AuditLogPageTests
         }
     }
 
+    [Fact]
+    public async Task DoubleClickTreeNode_OpensExecutionRowModal()
+    {
+        // Execution-Tree Node Detail Modal feature, Task 5: double-clicking a
+        // node on the /audit/execution-tree page opens ExecutionDetailModal —
+        // a modal listing that execution's audit rows, with click-through to
+        // each row's full <AuditEventDetail> view. We seed ONE execution with
+        // TWO audit rows (so the modal opens to the list view, not straight to
+        // a single-row detail), open the tree, double-click the node, walk
+        // list → row → detail, then close the modal.
+        if (!await AuditDataSeeder.IsAvailableAsync())
+        {
+            throw new InvalidOperationException("MSSQL unavailable; see FilterNarrowing test for setup instructions.");
+        }
+
+        var runId = Guid.NewGuid().ToString("N");
+        var targetPrefix = $"playwright-test/exec-node-modal/{runId}/";
+        var executionId = Guid.NewGuid();
+        var inboundEventId = Guid.NewGuid();
+        var outboundEventId = Guid.NewGuid();
+        var now = DateTime.UtcNow;
+
+        try
+        {
+            // Two rows sharing the same ExecutionId — an inbound request and an
+            // outbound call it made. The shared ExecutionId makes the tree node
+            // multi-row, so the modal lands on the list view.
+            await AuditDataSeeder.InsertAuditEventAsync(
+                eventId: inboundEventId,
+                occurredAtUtc: now,
+                channel: "ApiInbound",
+                kind: "InboundRequest",
+                status: "Delivered",
+                target: targetPrefix + "inbound",
+                executionId: executionId,
+                httpStatus: 200,
+                durationMs: 9);
+
+            await AuditDataSeeder.InsertAuditEventAsync(
+                eventId: outboundEventId,
+                occurredAtUtc: now,
+                channel: "ApiOutbound",
+                kind: "ApiCall",
+                status: "Delivered",
+                target: targetPrefix + "outbound",
+                executionId: executionId,
+                httpStatus: 200,
+                durationMs: 21);
+
+            var page = await _fixture.NewAuthenticatedPageAsync();
+
+            // Open the execution tree directly for the seeded execution.
+            await page.GotoAsync($"{PlaywrightFixture.BaseUrl}/audit/execution-tree?executionId={executionId}");
+            await page.WaitForLoadStateAsync(LoadState.NetworkIdle);
+
+            // The seeded execution renders as a tree node.
+            var nodeBody = page.Locator($"[data-test='tree-node-{executionId}'] .execution-tree-body");
+            await Assertions.Expect(nodeBody).ToBeVisibleAsync();
+
+            // Double-clicking the node body raises ExecutionTree's @ondblclick,
+            // which is a Blazor Server (InteractiveServer) handler — it only
+            // fires once the SignalR circuit is live. NetworkIdle can settle
+            // before the circuit connects, so a single early DblClick can be
+            // dropped. Retry the double-click until the modal appears.
+            var modal = page.Locator("[data-test='execution-detail-modal']");
+            for (var attempt = 0; attempt < 10 && await modal.CountAsync() == 0; attempt++)
+            {
+                await nodeBody.DblClickAsync();
+                try
+                {
+                    await modal.WaitForAsync(new() { State = WaitForSelectorState.Visible, Timeout = 1000 });
+                }
+                catch (TimeoutException)
+                {
+                    // Circuit not connected yet — loop and re-issue the dblclick.
+                }
+            }
+
+            await Assertions.Expect(modal).ToBeVisibleAsync();
+
+            // The modal opens on the list view — one button per audit row.
+            var inboundRow = page.Locator($"[data-test='execution-detail-row-{inboundEventId}']");
+            var outboundRow = page.Locator($"[data-test='execution-detail-row-{outboundEventId}']");
+            await Assertions.Expect(inboundRow).ToBeVisibleAsync();
+            await Assertions.Expect(outboundRow).ToBeVisibleAsync();
+
+            // Clicking a row switches the modal to that row's full detail —
+            // the shared <AuditEventDetail> field block renders.
+            await outboundRow.ClickAsync();
+            await Assertions.Expect(page.Locator("[data-test='drawer-fields']")).ToBeVisibleAsync();
+
+            // Closing the modal tears it down. The close click round-trips
+            // over the SignalR circuit before the @if(IsOpen) block re-renders
+            // away, so use the auto-retrying assertion rather than a bare
+            // CountAsync.
+            await page.Locator("[data-test='execution-detail-close']").ClickAsync();
+            await Assertions.Expect(modal).ToHaveCountAsync(0);
+        }
+        finally
+        {
+            await AuditDataSeeder.DeleteByTargetPrefixAsync(targetPrefix);
+        }
+    }
+
     [Fact]
     public async Task NotificationsPage_RendersAuditDrillInLinkPattern()
     {