feat(application): IAvisoQueryRepository + NullAvisoQueryRepository (CAT-002)

src/api/SIGCM2.Application/Abstractions/Persistence/IAvisoQueryRepository.cs

@@ -0,0 +1,24 @@
+namespace SIGCM2.Application.Abstractions.Persistence;
+
+/// <summary>
+/// Query-only access to Aviso counts by Rubro.
+/// CAT-002 introduces the contract. The real Dapper-based impl lands in PRD-002
+/// (when dbo.Aviso exists). Until then, NullAvisoQueryRepository is the binding.
+/// </summary>
+public interface IAvisoQueryRepository
+{
+    /// <summary>
+    /// Returns the count of avisos (active, non-archived) assigned to the given rubro.
+    /// </summary>
+    Task<int> CountAvisosEnRubroAsync(int rubroId, CancellationToken ct = default);
+
+    /// <summary>
+    /// Returns a dictionary of { rubroId → count } for the provided ids.
+    /// Used by GetRubroTreeQueryHandler to avoid N+1 when populating TieneAvisos per node.
+    /// The implementation MUST do a single query; the stub returns an empty dictionary
+    /// (every rubro gets 0 via dictionary.GetValueOrDefault).
+    /// </summary>
+    Task<IReadOnlyDictionary<int, int>> CountAvisosBatchAsync(
+        IReadOnlyCollection<int> rubroIds,
+        CancellationToken ct = default);
+}