Add tags for notes

I know that in Nextcloud Notes I can use Categories that are subfolders,
but I would find it more convenient to have Tags.
I have this functionnality with QownNotes but it can't synchronize with Nextcloud Notes keeping tags.
I first started an issue on QownNotes (https://github.com/pbek/QOwnNotes/issues/953) but here's what they answered:

@makayabou It appears that the Nextcloud notes app supports "categories", which is actually subdirectory, but does not support tags. Since tags are apparently in use and supported as a client-side feature for multiple clients of the Nextcloud notes app, lack of support for tags could be considered a design limitation in the notes app. Have you considered submitting a feature request to that project? The developers may have considered it redundant with categories, but if it is useful to the user base, they may want to know.
If it is implemented, it could be simply supported by the API using the "Get all notes" call, which returns to the client a list of notes and their attributes, which could be augmented to include a list of tags for each note (see Notes API 0.2). Support in QOwnNotes would be possible if, the developers are interested in adding it. Although it would require a few design changes in QOwnNotes to talk directly the the notes app, it would not require a separate request for each note to synchronize state.

What do you think of it ?

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Start by reviewing the Notes API 0.2 and the “Get all notes” call mentioned in the issue to understand how note attributes are exposed. Determine how tags should be represented and synchronized, then verify that clients can receive each note’s tags without separate requests. The issue does not name implementation files or tests.