refactor: star rating

[meesfrensel]

Description

Small refactor of the star rating system:

• Add null to mean 'unrated'. 0 is not used anymore, metadata extract/write jobs convert from/to 0 to ensure proper values are saved.
• Translation is updated to include special cases for -1 (rejected) and 0 (unrated).
• Asset update endpoint converts 0 to null before passing through to the service.
• Use mdi stars instead of custom svg
• Search option & query chip is updated
• Migration to convert all exif_info's rating=0 to rating=null

Fixes #26139

Changes to mobile app can be done separately because the server migrates to null and further changes with { rating: 0 } are auto transformed to null as well.

How Has This Been Tested?

• Extra unit tests
• Manually checked the correct xmp sidecar contents
• Inspected API responses

API Changes

• The search endpoint now accepts null as a rating filter
• The asset update endpoints now accept null as a valid rating to write
  • rating: 0 is transformed to null
• (the GET endpoints containing exifinfo already had number | null as the rating data type)

Please describe to which degree, if any, an LLM was used in creating this pull request.

None

[meesfrensel]

e2e test failures seem unrelated. The order of the faces is swapped?

[YarosMallorca]

This is great, but needs coordination with the mobile app to be effective.
Will work on the mobile implementation in the coming days.

[meesfrensel]

@YarosMallorca I don't think it's required actually (but best of course). The rating could already be undefined for 'not set' which translates to null in the app right? And when updating the rating from the app, the request to PUT /api/assets/:id will auto transform the rating: 0 to null.

[YarosMallorca]

Oh yes, correct. Missed that it converts 0 to null. Then it's all fine! Actually, the mobile app can't send nulls apparently anyway.

[danieldietzler]

This looks great actually, thanks!

[danieldietzler]

What does "Rejected" even mean in this context? Usually it's rather bad to use a magic number like -1 to report such a state

[meesfrensel]

It was introduced as being a valid exif rating in #15699. I can imagine using workflows or scripts you would use it to auto-archive assets, or when using an external tool to browse your library, etc. Unless you search for a rating and then explicitly change the url to use rating=-1, you'll never see that string.

[danieldietzler]

We don't really see that use case. Could you update the PR to only support 1-5, and everything else becomes invalid (unrated)