The tip channel is upstream's release strategy; this fork stopped publishing it when releases moved to the local notarized pipeline, and SparkleUpdateDelegate.allowedChannels has returned [] unconditionally since then — the Settings picker and the UpdateChannel plumbing were dead weight. Removes the enum, the GlobalSettings field (old prowl.json keys are ignored on decode), the applySettings/setUpdateChannel path, and the picker UI; folds the updateCheckInterval setup into configure. Sentry environment is now always production.