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.

src/ClaudeDo.Ui/Design/IslandStyles.axaml

@@ -116,6 +116,7 @@
     <SolidColorBrush x:Key="DraftBadgeBrush"    Color="{StaticResource TextMuteColor}"/>
     <SolidColorBrush x:Key="PlanningBadgeBrush" Color="{StaticResource PeatColor}"/>
     <SolidColorBrush x:Key="PlannedBadgeBrush"  Color="{StaticResource SageColor}"/>
+    <SolidColorBrush x:Key="ManualBadgeBrush"   Color="{StaticResource TextFaintColor}"/>
 
   </Styles.Resources>
 
@@ -1031,6 +1032,11 @@
     <Setter Property="Background" Value="{DynamicResource PlannedBadgeBrush}"/>
   </Style>
 
+  <!-- manual → faint gray: a reminder Claude never touches -->
+  <Style Selector="Border.badge.manual">
+    <Setter Property="Background" Value="{DynamicResource ManualBadgeBrush}"/>
+  </Style>
+
   <!-- ============================================================ -->
   <!-- SHARED MODAL STYLES (promoted from per-modal Window.Styles)  -->
   <!-- ============================================================ -->