fix: show image viewer for video-to-gif/webp results instead of broken video player

When a video tool produces a non-video output (gif, webp, png), the
media player can't render it. Now detects the processed file extension
and switches to ImageViewer for image outputs while keeping the video
player for the input preview.

apps/web/src/pages/tool-page.tsx

@@ -641,6 +641,20 @@ export function ToolPage() {
           );
         }
       }
+      // Tools that convert video to a non-video format (gif, webp, frames):
+      // after processing, show the result as an image instead of a video player
+      if (hasProcessed && processedUrl) {
+        const ext = (currentEntry?.processedFilename ?? "").split(".").pop()?.toLowerCase();
+        if (ext && ["gif", "webp", "png", "jpg", "jpeg", "apng"].includes(ext)) {
+          return (
+            <ImageViewer
+              src={processedUrl}
+              filename={currentEntry?.processedFilename ?? ""}
+              fileSize={currentEntry?.processedSize ?? 0}
+            />
+          );
+        }
+      }
       return (
         <Suspense fallback={<div className="text-sm text-muted-foreground">Loading...</div>}>
           <MediaPlayerView />