fix(worker,ui): clean up three review leftovers from the list-handler run

Remove the redundant TaskUpdated broadcast in TaskRunner.ContinueAsync's
queue-claim path, consolidate InteractiveLaunchSpecService's seven
MCP_TOOL_TIMEOUT literals into one constant (fixing the merge-helper handoff
spec's stale 200000ms value), and surface OpenQuickClaudeSession's two
failure cases via ErrorReported/footer instead of a silent no-op, with a
less ambiguous icon.

src/ClaudeDo.Ui/Views/Islands/TasksIslandView.axaml

@@ -39,7 +39,7 @@
           </Button>
           <Button Classes="icon-btn" IsVisible="{Binding IsQuickClaudeVisible}"
                   Command="{Binding OpenQuickClaudeSessionCommand}" ToolTip.Tip="{loc:Tr tasks.quickClaudeTip}">
-            <PathIcon Width="15" Height="15" Data="{StaticResource Icon.Plus}"/>
+            <PathIcon Width="15" Height="15" Data="{StaticResource Icon.ArrowOut}"/>
           </Button>
           <Button Classes="icon-btn" IsVisible="{Binding IsMyDayList}"
                   Command="{Binding ClearDayCommand}" ToolTip.Tip="{loc:Tr tasks.clearDayTip}">