Add setting for notification worktree reordering

[khoi]

• add a global setting moveNotifiedWorktreeToTop (default enabled) and expose it in Notifications settings as "Move notified worktree to top"
• gate .worktreeNotificationReceived reordering behavior on that setting
• move the toggle into RepositoriesFeature.State and wire updates from AppFeature settings fan-out so notifications no longer read @Shared(.settingsFile) in the hot path
• add regression coverage for disabled reordering, reducer state updates, and app-level settings propagation
• add persistence/settings test updates for the new global field
• validate with make check, targeted xcodebuild test runs for affected suites, and make build-app