Fix tray animation stutter

[handlecusion]

Summary

• disable implicit Core Animation actions around tray CALayer contents/frame updates
• add the CATransaction feature needed for action-disabled layer transactions
• prevent the menubar cat from briefly pausing or coalescing while frames swap

Validation

• cargo check --locked
• cargo test --locked
• git diff --check -- src-tauri/Cargo.toml src-tauri/src/native_tray.rs