feat(tasks): mark tasks and lists as manual

Reminders written down as todos had no home: every task looked like Claude work.
A manual task now shows a MANUAL badge and hides send-to-queue, refine and the
planning session; the queue picker, daily prep and the list handler all skip it,
with a TaskStateService guard so the MCP surface and hub cannot start one either.
Opening a hand-driven ConPTY session stays available on purpose.

A list can be marked manual in its settings, which makes tasks created there
(UI and MCP add_task) start out manual. Toggle per task from its context menu.

tests/ClaudeDo.Worker.Tests/Queue/QueuePickerTests.cs

@@ -48,7 +48,8 @@ public sealed class QueuePickerTests : IDisposable
         DateTime? scheduledFor = null,
         string? blockedBy = null,
         bool taskAgentTag = false,
-        int? sortOrder = null)
+        int? sortOrder = null,
+        bool isManual = false)
     {
         var task = new TaskEntity
         {
@@ -60,6 +61,7 @@ public sealed class QueuePickerTests : IDisposable
             ScheduledFor = scheduledFor,
             BlockedByTaskId = blockedBy,
             CommitType = "feat",
+            IsManual = isManual,
         };
         await _tasks.AddAsync(task);
         if (sortOrder is not null)
@@ -70,6 +72,28 @@ public sealed class QueuePickerTests : IDisposable
         return task;
     }
 
+    [Fact]
+    public async Task ClaimNextAsync_Skips_ManualTasks()
+    {
+        var listId = await CreateListAsync();
+        await SeedAsync(listId, isManual: true);
+
+        Assert.Null(await _picker.ClaimNextAsync(DateTime.UtcNow, CancellationToken.None));
+    }
+
+    [Fact]
+    public async Task ClaimNextAsync_Skips_ManualTask_ButClaimsTheNextOne()
+    {
+        var listId = await CreateListAsync();
+        await SeedAsync(listId, createdAt: DateTime.UtcNow.AddMinutes(-5), isManual: true);
+        var claudeTask = await SeedAsync(listId, createdAt: DateTime.UtcNow);
+
+        var picked = await _picker.ClaimNextAsync(DateTime.UtcNow, CancellationToken.None);
+
+        Assert.NotNull(picked);
+        Assert.Equal(claudeTask.Id, picked!.Id);
+    }
+
     [Fact]
     public async Task ClaimNextAsync_Skips_TasksWithBlockedByTaskId()
     {