fix: accessibility, progress monotonicity, speed guard, and flaky test

- AnnotationNode: add aria-label and focus-visible styles to download btn
- AudioInputNode: same accessibility fix for download button
- useStitchVideos: fix non-monotonic progress (8 -> 11 after 10)
- useTypewriter: guard speed with Math.max(16, speed) minimum
- loopEdge test: replace setTimeout race with vi.waitFor polling

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

src/components/nodes/AnnotationNode.tsx

@@ -136,7 +136,8 @@ export function AnnotationNode({ id, data, selected }: NodeProps<AnnotationNodeT
               e.stopPropagation();
               downloadMedia(displayImage!, "image");
             }}
-            className="absolute top-2 right-10 w-6 h-6 bg-black/60 hover:bg-black/80 text-white rounded text-xs opacity-0 group-hover:opacity-100 transition-opacity flex items-center justify-center"
+            aria-label="Download image"
+            className="absolute top-2 right-10 w-6 h-6 bg-black/60 hover:bg-black/80 text-white rounded text-xs opacity-0 group-hover:opacity-100 focus-visible:opacity-100 focus-visible:ring-1 focus-visible:ring-white transition-opacity flex items-center justify-center"
           >
             <svg className="w-3.5 h-3.5" fill="none" viewBox="0 0 24 24" stroke="currentColor" strokeWidth={2}>
               <path strokeLinecap="round" strokeLinejoin="round" d="M4 16v1a3 3 0 003 3h10a3 3 0 003-3v-1m-4-4l-4 4m0 0l-4-4m4 4V4" />

src/components/nodes/AudioInputNode.tsx

@@ -217,7 +217,8 @@ export function AudioInputNode({ id, data, selected }: NodeProps<AudioInputNodeT
           {/* Download button */}
           <button
             onClick={() => downloadMedia(nodeData.audioFile!, "audio")}
-            className="absolute top-1 right-7 w-5 h-5 bg-black/60 hover:bg-black/80 text-white rounded text-xs opacity-0 group-hover:opacity-100 transition-opacity flex items-center justify-center"
+            aria-label="Download audio"
+            className="absolute top-1 right-7 w-5 h-5 bg-black/60 hover:bg-black/80 text-white rounded text-xs opacity-0 group-hover:opacity-100 focus-visible:opacity-100 focus-visible:ring-1 focus-visible:ring-white transition-opacity flex items-center justify-center"
             title="Download audio"
           >
             <svg className="w-3 h-3" fill="none" viewBox="0 0 24 24" stroke="currentColor" strokeWidth={2}>

src/hooks/useStitchVideos.ts

@@ -295,7 +295,7 @@ export async function stitchVideosAsync(
     let outputStarted = false;
 
     if (effectiveAudioData) {
-      updateProgress('processing', 'Detecting supported audio codec...', 8);
+      updateProgress('processing', 'Detecting supported audio codec...', 11);
 
       // Detect the best supported audio codec for MP4
       // Try common codecs in order of preference: aac, mp3 (no opus - Twitter doesn't support it)

src/hooks/useTypewriter.ts

@@ -13,6 +13,7 @@ interface UseTypewriterResult {
  * @returns Object with displayedText (current partial text) and isComplete (true when done)
  */
 export function useTypewriter(text: string, speed: number = 50): UseTypewriterResult {
+  const safeSpeed = Math.max(16, speed);
   const [displayedText, setDisplayedText] = useState("");
   const [currentIndex, setCurrentIndex] = useState(0);
 
@@ -38,10 +39,10 @@ export function useTypewriter(text: string, speed: number = 50): UseTypewriterRe
         }
         return nextIndex;
       });
-    }, speed);
+    }, safeSpeed);
 
     return () => clearInterval(timer);
-  }, [text, speed, currentIndex]);
+  }, [text, safeSpeed, currentIndex]);
 
   return {
     displayedText,

src/store/__tests__/loopEdge.integration.test.ts

@@ -214,10 +214,12 @@ describe("executeWorkflow with loop edges", () => {
     // Start execution (don't await)
     const executionPromise = useWorkflowStore.getState().executeWorkflow();
 
-    // Abort after a short delay
+    // Poll until execution has actually started before stopping
-    setTimeout(() => {
+    await vi.waitFor(() => {
-      useWorkflowStore.getState().stopWorkflow();
+      expect(useWorkflowStore.getState().isRunning).toBe(true);
-    }, 10);
+    }, { timeout: 1000 });
+
+    useWorkflowStore.getState().stopWorkflow();
 
     await executionPromise;