Visage 1.0.4

Fixes the in-app update checker — it previously failed silently on every version since 1.0.0, so updating to 1.0.4 requires downloading this release once; all later updates arrive in-app. Redesigned update notifications: clear checking / up-to-date / update-available states with version numbers, centred Update & Dismiss actions, an inline Update button in Settings, and an update check on every launch (silent unless something is found; nothing ever installs without your click).