⚡ Bolt: Use binary search in onTimeUpdate for better playback performance

[benpiper]

• 💡 What: Replaced the O(N) linear search loop in handleTimeUpdate with an O(log N) binary search algorithm, and added an explanatory comment.
• 🎯 Why: handleTimeUpdate is triggered very frequently by <video onTimeUpdate>. Iterating sequentially through potentially large arrays of timestamps can block the main thread.
• 📊 Impact: Lookups scale logarithmically instead of linearly, preventing CPU spikes and jank during playback of long videos.
• 🔬 Measurement: Observe CPU usage profiling during playback in the browser dev tools, and ensure playback remains smooth. Ensure timeline scrolling still syncs.

---

PR created automatically by Jules for task 15517346830319619168 started by @benpiper

[google-labs-jules]

👋 Jules, reporting for duty! I'm here to lend a hand with this pull request.

When you start a review, I'll add a 👀 emoji to each comment to let you know I've read it. I'll focus on feedback directed at me and will do my best to stay out of conversations between you and other bots or reviewers to keep the noise down.

I'll push a commit with your requested changes shortly after. Please note there might be a delay between these steps, but rest assured I'm on the job!

For more direct control, you can switch me to Reactive Mode. When this mode is on, I will only act on comments where you specifically mention me with @jules. You can find this option in the Pull Request section of your global Jules UI settings. You can always switch back!

New to Jules? Learn more at jules.google/docs.

---

For security, I will only act on instructions from the user who triggered this task.