feat(auditlog): GetExecutionTreeAsync recursive execution-chain query

src/ScadaLink.Commons/Interfaces/Repositories/IAuditLogRepository.cs

@@ -134,4 +134,45 @@ public interface IAuditLogRepository
         TimeSpan window,
         DateTime? nowUtc = null,
         CancellationToken ct = default);
+
+    /// <summary>
+    /// Audit Log ParentExecutionId feature (Task 8) — given any
+    /// <paramref name="executionId"/> in an execution chain, returns the whole
+    /// chain rooted at the topmost ancestor: one <see cref="ExecutionTreeNode"/>
+    /// per distinct execution, summarising its <c>AuditLog</c> rows. The Central
+    /// UI renders the result as a tree.
+    /// </summary>
+    /// <remarks>
+    /// <para>
+    /// The input id may be any node in the chain — a leaf, the root, or a middle
+    /// node. The implementation first walks <em>up</em> via
+    /// <c>ParentExecutionId</c> to find the root, then walks <em>down</em> from
+    /// the root via a recursive CTE, so the full chain is returned regardless of
+    /// entry point.
+    /// </para>
+    /// <para>
+    /// The <c>ParentExecutionId</c> graph is a tree (acyclic by construction —
+    /// each execution is minted fresh and its parent always pre-exists). Both
+    /// the upward walk and the downward CTE are nonetheless bounded at 32 levels
+    /// as a guard against corrupt/pathological data: a depth that exceeds the
+    /// guard raises an error rather than hanging the server. Chains are shallow
+    /// (1-2 levels typical) so the guard is never reached in practice.
+    /// </para>
+    /// <para>
+    /// A "stub" node — an execution that emitted no rows of its own yet is
+    /// referenced by a child via <c>ParentExecutionId</c>, or whose rows have
+    /// been purged — still appears, with <see cref="ExecutionTreeNode.RowCount"/>
+    /// = 0. A purged/missing parent simply ends the upward walk.
+    /// </para>
+    /// <para>
+    /// When no <c>AuditLog</c> row carries <paramref name="executionId"/> in
+    /// either <c>ExecutionId</c> or <c>ParentExecutionId</c>, the result is a
+    /// single stub node for <paramref name="executionId"/> itself
+    /// (<see cref="ExecutionTreeNode.RowCount"/> = 0) — consistent with the
+    /// stub-node treatment of any other row-less execution.
+    /// </para>
+    /// </remarks>
+    Task<IReadOnlyList<ExecutionTreeNode>> GetExecutionTreeAsync(
+        Guid executionId,
+        CancellationToken ct = default);
 }