Fix Linux build: enable ksni feature for tray-item and add libdbus-1-dev to CI

Co-authored-by: Cursor <cursoragent@cursor.com>

.github/workflows/ci.yml

@@ -13,6 +13,10 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
+      - name: Install system dependencies (Linux)
+        if: runner.os == 'Linux'
+        run: sudo apt-get update && sudo apt-get install -y libdbus-1-dev pkg-config
+
       - name: Install Rust toolchain
         uses: dtolnay/rust-toolchain@stable