Replaces our custom `<GlobalSnackbar />` (MUI Snackbar + event emitter)
with [`sonner`](https://github.com/emilkowalski/sonner). Deletes
`GlobalSnackbar/`, the custom event emitter infra, and migrates ~80
source files to `toast.success()` / `toast.error()` from `sonner`.
- ~47 error toasts now surface API error detail via
`getErrorDetail(error)` in the toast description, not just a generic
message. Coincides with #22229.
- Toast messages follow an `{Action} "{entity}" {result}.` format (e.g.
`User "alice" suspended successfully.`) since toasts persist across
navigation now.
- 17 uses of `toast.promise()` for loading → success → error lifecycle.
- Some toasts include action buttons for quick navigation (e.g. "View
task", "View template").
- Multiple toasts can stack and display simultaneously.
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Co-authored-by: Kayla はな <mckayla@hey.com>
Closescoder/internal#168
Gets rid of the "global state" authentication, and adds a `login` helper
which should be called at the beginning of each test. This means that
not every test needs to authenticated as admin, and we can even have
tests that encompass multiple permission levels.
We also now create more than just the single admin user during setup, so
that we can have a set of users to pick from as appropriate.
Jake Howell