feat(deploy): pending-deployment repository with supersession + purge

src/ZB.MOM.WW.ScadaBridge.ConfigurationDatabase/Repositories/DeploymentManagerRepository.cs

@@ -197,6 +197,60 @@ public class DeploymentManagerRepository : IDeploymentManagerRepository
         }
     }
 
+    // --- Notify-and-fetch: PendingDeployment staging store ---
+
+    /// <inheritdoc />
+    public async Task AddPendingDeploymentAsync(PendingDeployment pending, CancellationToken cancellationToken = default)
+    {
+        ArgumentNullException.ThrowIfNull(pending);
+
+        // Supersession: a newer deploy for the same instance replaces any prior pending
+        // row. Safe because the per-instance operation lock serializes same-instance
+        // deploys. SaveChanges is deferred to the caller, matching the other Add methods.
+        var prior = await _dbContext.Set<PendingDeployment>()
+            .Where(p => p.InstanceId == pending.InstanceId)
+            .ToListAsync(cancellationToken);
+        if (prior.Count > 0)
+        {
+            _dbContext.Set<PendingDeployment>().RemoveRange(prior);
+        }
+        await _dbContext.Set<PendingDeployment>().AddAsync(pending, cancellationToken);
+    }
+
+    /// <inheritdoc />
+    public Task<PendingDeployment?> GetPendingDeploymentByIdAsync(string deploymentId, CancellationToken cancellationToken = default)
+    {
+        return _dbContext.Set<PendingDeployment>()
+            .FirstOrDefaultAsync(p => p.DeploymentId == deploymentId, cancellationToken);
+    }
+
+    /// <inheritdoc />
+    public async Task DeletePendingDeploymentByIdAsync(string deploymentId, CancellationToken cancellationToken = default)
+    {
+        var row = await _dbContext.Set<PendingDeployment>()
+            .FirstOrDefaultAsync(p => p.DeploymentId == deploymentId, cancellationToken);
+        if (row != null)
+        {
+            _dbContext.Set<PendingDeployment>().Remove(row);
+        }
+    }
+
+    /// <inheritdoc />
+    public async Task<int> PurgeExpiredPendingDeploymentsAsync(DateTimeOffset nowUtc, CancellationToken cancellationToken = default)
+    {
+        // Self-contained TTL maintenance op: commits its own delete and returns the count.
+        var expired = await _dbContext.Set<PendingDeployment>()
+            .Where(p => p.ExpiresAtUtc <= nowUtc)
+            .ToListAsync(cancellationToken);
+        if (expired.Count == 0)
+        {
+            return 0;
+        }
+        _dbContext.Set<PendingDeployment>().RemoveRange(expired);
+        await _dbContext.SaveChangesAsync(cancellationToken);
+        return expired.Count;
+    }
+
     // --- Instance lookups for deployment pipeline ---
 
     /// <inheritdoc />