feat(data): persist max_turns in list and task repositories

Add MaxTurns to ListRepository.SetConfigAsync upsert branch and
TaskRepository.UpdateAgentSettingsAsync; fix positional CancellationToken
call in ConfigMcpTools. Covered by MaxTurnsRoundTripTests (2 tests).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/ClaudeDo.Worker.Tests/Repositories/MaxTurnsRoundTripTests.cs

@@ -0,0 +1,79 @@
+using ClaudeDo.Data;
+using ClaudeDo.Data.Models;
+using ClaudeDo.Data.Repositories;
+using ClaudeDo.Worker.Tests.Infrastructure;
+
+namespace ClaudeDo.Worker.Tests.Repositories;
+
+public sealed class MaxTurnsRoundTripTests : IDisposable
+{
+    private readonly DbFixture _db = new();
+
+    public void Dispose() => _db.Dispose();
+
+    [Fact]
+    public async Task ListConfig_persists_max_turns()
+    {
+        var listId = Guid.NewGuid().ToString();
+        using (var ctx = _db.CreateContext())
+        {
+            await new ListRepository(ctx).AddAsync(new ListEntity
+            {
+                Id = listId, Name = "L", CreatedAt = DateTime.UtcNow,
+            });
+        }
+
+        using (var ctx = _db.CreateContext())
+        {
+            await new ListRepository(ctx).SetConfigAsync(new ListConfigEntity
+            {
+                ListId = listId, MaxTurns = 42,
+            });
+        }
+
+        using var readCtx = _db.CreateContext();
+        var config = await new ListRepository(readCtx).GetConfigAsync(listId);
+        Assert.NotNull(config);
+        Assert.Equal(42, config!.MaxTurns);
+    }
+
+    [Fact]
+    public async Task Task_agent_settings_persist_and_clear_max_turns()
+    {
+        var listId = Guid.NewGuid().ToString();
+        var taskId = Guid.NewGuid().ToString();
+        using (var ctx = _db.CreateContext())
+        {
+            await new ListRepository(ctx).AddAsync(new ListEntity
+            {
+                Id = listId, Name = "L", CreatedAt = DateTime.UtcNow,
+            });
+            await new TaskRepository(ctx).AddAsync(new TaskEntity
+            {
+                Id = taskId, ListId = listId, Title = "t", CreatedAt = DateTime.UtcNow,
+            });
+        }
+
+        using (var ctx = _db.CreateContext())
+        {
+            await new TaskRepository(ctx).UpdateAgentSettingsAsync(taskId, null, null, null, maxTurns: 7);
+        }
+
+        using (var ctx = _db.CreateContext())
+        {
+            var entity = await new TaskRepository(ctx).GetByIdAsync(taskId);
+            Assert.NotNull(entity);
+            Assert.Equal(7, entity!.MaxTurns);
+        }
+
+        using (var ctx = _db.CreateContext())
+        {
+            await new TaskRepository(ctx).UpdateAgentSettingsAsync(taskId, null, null, null, maxTurns: null);
+        }
+
+        using var readCtx = _db.CreateContext();
+        var final = await new TaskRepository(readCtx).GetByIdAsync(taskId);
+        Assert.NotNull(final);
+        Assert.Null(final!.MaxTurns);
+    }
+}