V4.0.2

- Fix spurious SyncUp every few seconds when Git LFS left a stale
  .git/lfs/is_behind marker; run SyncDown when LFS catch-up is needed
- Run git lfs pull only when the remote has new commits or the marker
  exists, not on every poll
- About dialog: check markusstoll/SparkleShare GitHub releases/latest
  for updates instead of sparkleshare.org

- After wake from sleep, run sync on a background thread (avoids UI freeze)
- About: single-line update hint with clickable “(download)” link;
  shorter credits text; layout fixes for original window size
- About shows CFBundleShortVersionString from the app bundle (matches
  Finder / Get Info)
- Release builds: dotnet clean per architecture in release-mac-dmgs.sh;
  Release rebuild in build-mac.sh to avoid stale MonoBundle DLLs

First rebuild on .NET 10 for Mac

- Migrate core libraries (Sparkles, Sparkles.Git) to .NET 10 (SDK-style projects)
- Add SparkleShare.Core.sln with unit tests and GitHub Actions CI
- Replace obsolete .NET APIs (WebRequest, reflection, URI handling, time zones)
- Reactivate announcement listeners (no hard-coded default service URL)
- Tray menu: "Force Pull" per synced folder
- Git over SSH: always use SparkleShare's own key; ignore ssh-agent
  (IdentityAgent=none) to avoid hangs when an agent is missing or broken
- Refresh Git LFS filter/hook SSH settings on repo load; backfill storage_type
  in projects.xml when LFS filters are present
- New SDK-style app (net10.0-macos), minimum macOS 12
- Replace deprecated WebView with WKWebView in event log
- Fix remaining AppKit deprecations; Release build is warning-free
- Prevent multiple app instances (NSRunningApplication)
- Keep existing config under ~/.config/org.sparkleshare.SparkleShare
- Bundle matching Dugite git + git-lfs per CPU architecture (arm64 / Intel)
- Release scripts: build, sign, notarize, and staple separate DMGs
  (scripts/release-mac-dmgs.sh → SparkleShare_4.0.1-beta_arm64.dmg and _x64.dmg)
- Remove legacy SparkleShareInviteOpener.app (register sparkleshare:// in-app: TODO)
- Debug builds can fall back to system git when the bundle is not present