Let a paused flow be stepped from the dock

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01H7LwYgJfpkbLCTeiAf8U4A

frontend/src/components/Flow/FlowDock.tsx

@@ -9,6 +9,7 @@ import {
   Play,
   PlayCircle,
   Plus,
+  StepForward,
   WifiOff,
   ZoomIn,
   ZoomOut,
@@ -62,6 +63,8 @@ export function FlowDock({
   onAddNode,
   onRun,
   onTogglePause,
+  onStep,
+  stepping,
   onFocusNode,
   onEditFlow,
   onPublish,
@@ -79,6 +82,8 @@ export function FlowDock({
   onAddNode: () => void
   onRun: () => void
   onTogglePause: () => void
+  onStep: () => void
+  stepping: boolean
   onFocusNode: (nodeId: string) => void
   onEditFlow: () => void
   onPublish: () => void
@@ -214,6 +219,25 @@ export function FlowDock({
         </TooltipContent>
       </Tooltip>
 
+      {paused && enabled ? (
+        <Tooltip>
+          <TooltipTrigger asChild>
+            <Button
+              variant="ghost"
+              size="icon"
+              className="size-11 text-muted-foreground md:size-8"
+              onClick={onStep}
+              disabled={stepping}
+              aria-label="Step the flow"
+              data-testid="step-flow"
+            >
+              <StepForward />
+            </Button>
+          </TooltipTrigger>
+          <TooltipContent>Let one held-back item through</TooltipContent>
+        </Tooltip>
+      ) : null}
+
       <Tooltip>
         <TooltipTrigger asChild>
           <span>