Display parsing errors reported from the backend on the frontend via Toast error messages

[sinanm89]

Description

Currently there isnt a way to know what edit error caused the acl.hujson to have issues.

if and when you do make an error on the file it will 'refresh' the contents and give you a 502 failiure error without any explanation as to why (have to inspect the response and view from there).

this content refresh causes one major issue; all of your previous edits are now discarded and youre at the last saved file. aka your edits are gone.

so to make it a bit more user friendly and not to have some good edits vanish (also to make the discard changes button useful as a byproduct) I made these edits where the parsing error will be displayed on the same spot as the acl edit saved toast pops up as a red notification, it doesnt vanish until the user refreshes the page or clears it (meaning they read and acknowledged the error).

Failiure:

Success:

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Ive made some assumptions and generified the error handling with classes but tried not to change anything on the structure of the code & existing behaviour. Currently i have it running on my own stack and can create a small demo page to test the feature/bug-fix.

Please feel free to correct me on parts where i took liberties, id like to continue contributing with qol if possible.

#391

Headplane Version

v0.6.1

Headscale Version

v0.27.1