Organize devices in the webUI with tags or folders

**Describe the problem you have/What new integration you would like**

A method to organize individual devices in the UI - tags, folders, or something like that.

**Please describe your use case for this integration and alternatives you've tried:**

I have a lot (20+) devices configured in ESPHome. I mostly use the WebUI to manage these devices, but it's getting a little difficult to stay organized. In particular, I'd like to be able to have a persistent filter so that I can show/hide devices that I'm not working on right now.

**Additional context**

The issue names no files, tests, or entry points. Start by reviewing the webUI device list and its current filtering and organization behavior, then clarify whether tags, folders, or persistent filters are required. Done means users can organize devices and reliably show or hide selected groups.

Written by the indexing model from the issue text.