Function task_notification 

pub fn task_notification(
    label: &str,
    outcome: &TaskOutcome,
) -> (NotificationLevel, String)

NC.2: how a finished background task reads.

Pure, so the wording is tested without a bus. The label is an imperative phrase naming its object (“push main → origin/main”); the outcome is appended here, in one place, so every producer reads the same way:

Outcome	Level	Text
succeeded	Success	label — summary, or just label
stopped	Warn	label stopped — message
failed	Error	label failed — message

Success needs no “finished” — the check says it — and the icon does not stand alone for the other two: the word is what *messages* keeps, and what a reader without colour sees.