New plugin: FavouriteAnything

[Davr1]

This plugin allows you to add common media and file types to your favourites (including images, videos, audio files, text files, content within rich embeds, external youtube/tiktok embeds, cv2 file/media components, clips, etc), and is compatible with the vanilla client, so anything you favourite will be displayed in the gif picker as a regular image/video (if possible) or a simple thumbnail with the proper source url.

Favorite button is displayed either on the left for basic attachments, or on the right grouped with other actions

Favourite files live in a separate tab, and are fully interactive. Plugin is made to be extensible so adding another type of favouritable item would take ~50 lines tops, however the split between "media" and "files" already covers most use cases

What custom non-media items look like with the plugin disabled. Clicking on the thumbnail will send the original attachment url. Attachments are still searchable given the fact that the filename is used in the thumbnail url itself

This plugin has been in Equicord (and vencor #unofficial-plugins) for a while now so most edge cases are already handled correctly.
Supersedes #2091.

Checklist before submitting

• I have read the CONTRIBUTING.md file and made sure this pull request complies with it
• This pull request was written by me, and not an AI agent

[Davr1]

I can finally remove the polyfill

[Davr1]

Updated the attachment thumbnails to use tiny svgs instead of an external placeholder image service (Thanks fres!)

This also means one less patch since the thumbnail can be generated fairly cheaply at runtime

[nin0-dev]

does it work on iPhone

[Davr1]

Mobile can't render inline svgs I think (haven't tested on iphone)
at least the expression picker search still works so if you know what the file is called you can find it blindly

Maybe I could add a toggle to choose between inline svg and external bitmap thumbnails (which would have to use an external service, since storing a bitmap in the protobuf would be really wasteful)

[Davr1]

Added mobile compatible thumbnails generated with placeholder.nin0.dev