Dayflow 2.4.2 crashes Sonoma

[finteractive]

Dayflow 2.4.2 (build 125) crashes on launch on macOS 14.8.2 (Sonoma, Apple Silicon) and 14.8.9

Downgrading to 2.4.0 fixes it, so this looks like a regression in 2.4.2 and possibly Sonoma-specific if no one else sees any issues with 2.4.2.

Crash is on the main thread, EXC_BREAKPOINT (SIGTRAP), brk 1, with no error message on stderr and no Application Specific Information in the report.

Additional context

• macOS 14.8.2 (23J126), Mac15,7, arm64
• LSMinimumSystemVersion in the bundle is 14.0, so Sonoma is supported
• Ruled out: clean reinstall, empty preferences domain (defaults delete reports the
  domain does not exist), NSRequiresAquaSystemAppearance = YES, and deleting
  ~/Library/Saved Application State/teleportlabs.com.Dayflow.savedState and
  ~/Library/Caches/teleportlabs.com.Dayflow
• Installing 2.4.0 resolves it. Worth noting Sparkle has autoDownloads=true with a 3600s
  interval, so a downgrade gets silently re-upgraded unless auto-updates are disabled first

[JacobZheng0927]

I can reproduce this on macOS 15.1 (24B2082), arm64, with Dayflow 2.4.2 (build 125), so this is not Sonoma-only. Directly launching the executable exits with code 133 / SIGTRAP.

I narrowed the trap to the new system appearance observer:

• A standalone AppKit probe returns NSAppearanceNameAqua, and bestMatch(from: [.aqua, .darkAqua]) also returns Aqua, so the appearance value itself is valid.
• Static disassembly of SystemAppearanceObserver.currentColorScheme shows it loading _NSApp, branching directly to brk #1 when the value is null.
• The crash report confirms x0 = 0 at that branch.

This matches the v2.4.2 source: DayflowTheme.swift#L28-L45. SystemAppearanceObserver.init() calls Self.currentColorScheme and then NSApp.observe(...) before NSApplication is guaranteed to exist.

A minimal fix should be to instantiate and consistently reuse the shared application before reading or observing it, for example:

let app = NSApplication.shared
colorScheme = app.effectiveAppearance.bestMatch(from: [.aqua, .darkAqua]) == .darkAqua ? .dark : .light
observation = app.observe(\.effectiveAppearance, options: [.new]) { ... }

Downgrading to 2.4.0 remains the working workaround.