Prep Mac app for release, fix bugs in iOS app (#258)

• Update Sparkle to latest version

• Bump minimum macOS target

For launch, I propose we support the current version of macOS (14.x) and one version earlier (13.x).

• Add WFNavigation wrapper to use NavigationSplitView in macOS

• Replace NavigationView with WFNavigation in ContentView

• Fix deprecation warnings on locale

• Update docs for updating the Mac app

• Fix for being sent back to post list on app reactivate

• Bump build version

• Remove debugging statements

• Bump Sparkle version to address security fix