Upgrade Chrome Timeslot Picker

I have a custom Google Chrome extension that is supposed to let me choose a booking time slot on a web page, yet the current build stalls at that very step. I need someone to dive into the existing codebase, identify why the slot-picker fails, and then add a more robust “enhanced time slot selection” feature so choosing and confirming a time becomes effortless.

The extension is already live in my browser, written in the usual combination of JavaScript, HTML, CSS, and the Chrome Extension APIs (manifest v3). You’ll have access to the source files plus a short video showing the exact moment the picker breaks. From there, your tasks are:

• Diagnose and fix the selection bug so the current UI works without errors.
• Replace or improve the slot-picker component with an upgraded version—think clearer layout, instant feedback on unavailable slots, and smooth confirmation.
• Hand back the updated source, a packaged version ready for loading in developer mode, and brief installation notes so I can test immediately.

Acceptance criteria: the time-slot UI loads in under two seconds, reflects availability accurately on every test page I provide, and lets me confirm a booking in one click without console errors.

Prefer solid experience with JavaScript ES6+, Chrome Extension APIs, DOM manipulation, and debugging tools. If you can suggest future add-ons such as user notifications or broader customization, flag them, but the core focus right now is the enhanced time slot selection.