fix(store-and-forward): page retry sweep per (category,target) lane; drop dead GetAllMessagesAsync (review 2026-10-21 02/C2, 02/U2)

tests/ZB.MOM.WW.ScadaBridge.StoreAndForward.Tests/StoreAndForwardStorageTests.cs

@@ -822,19 +822,35 @@ public class StoreAndForwardStorageTests : IAsyncLifetime, IDisposable
         Status = status,
     };
 
-    /// <summary>Verifies that the all-messages query returns every status, oldest first, up to the limit.</summary>
+    /// <summary>
+    /// Review 2026-10-21 02/C2: a dead target holding more due rows than the sweep page must not
+    /// starve a healthy target — the page is ranked per (category, target) lane, and each lane
+    /// stays oldest-first.
+    /// </summary>
     /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
-    public async Task GetAllMessages_ReturnsEveryStatus_OldestFirst_UpToLimit()
+    public async Task GetMessagesForRetry_PagesPerLane_DeadTargetCannotStarveOthers()
     {
-        var @base = DateTimeOffset.UtcNow;
-        await _storage.EnqueueAsync(NewMsg("p1", StoreAndForwardMessageStatus.Pending, @base));
-        await _storage.EnqueueAsync(NewMsg("k1", StoreAndForwardMessageStatus.Parked, @base.AddSeconds(1)));
-        await _storage.EnqueueAsync(NewMsg("p2", StoreAndForwardMessageStatus.Pending, @base.AddSeconds(2)));
+        var @base = DateTimeOffset.UtcNow.AddHours(-1);
+        for (var i = 0; i < 600; i++)
+        {
+            var m = NewMsg($"a{i:D3}", StoreAndForwardMessageStatus.Pending, @base.AddSeconds(i));
+            m.Target = "dead";
+            m.RetryIntervalMs = 0;
+            await _storage.EnqueueAsync(m);
+        }
+        var healthy = NewMsg("b0", StoreAndForwardMessageStatus.Pending, @base.AddSeconds(1000));
+        healthy.Target = "healthy";
+        healthy.RetryIntervalMs = 0;
+        await _storage.EnqueueAsync(healthy);
 
-        var (all, truncated) = await _storage.GetAllMessagesAsync(limit: 2);
-        Assert.Equal(new[] { "p1", "k1" }, all.Select(m => m.Id)); // every status, oldest-first
-        Assert.True(truncated); // a third row exists beyond the limit
+        var page = await _storage.GetMessagesForRetryAsync(500);
+
+        Assert.Equal(500, page.Count);
+        Assert.Contains(page, m => m.Id == "b0");
+        var dead = page.Where(m => m.Target == "dead").Select(m => m.Id).ToList();
+        Assert.Equal(dead.OrderBy(x => x).ToList(), dead); // per-target FIFO preserved
+        Assert.Equal("a000", dead[0]);
     }
 
     // ReplaceAll_SwapsTheEntireBuffer_Atomically was DELETED with ReplaceAllAsync in