unstable desktop-8-1

Desktop build, notification, and UI polish update.

Highlights:

• Added Apple notarization support for macOS desktop builds.
• Improved macOS build scripts and release workflow documentation.
• Routed desktop notifications through Tauri.
• Unified user-facing time display across the desktop UI.
• Improved provider card layout and source labels.
• Updated the provider status table.
• Refined DevOps and desktop build documentation.

Notes:

• Unstable preview build.
• macOS build is signed, notarized, and stapled.
• Windows and Linux builds are unsigned.