Progress bar is "left hanging" when page loads too quickly

### 📝 Describe the bug

Sometimes when navigating between pages, they can load too quickly for the progress bar to react, causing it to continually be in a loading state even though the page has loaded fully.

### 🔄 To Reproduce

1. Go to a page
2. Go to a page that has been loaded before (which is cached and should load very quickly)
3. Watch the progress bar

### 📷 Screenshots

_No response_

### 💡 Additional context

_No response_

No file, test, or entry point is named. First reproduce the issue by navigating to a previously loaded, cached page and inspect the progress-bar implementation and navigation lifecycle. Done means the progress bar reliably stops when a fast page load completes.

Written by the indexing model from the issue text.