fix(deb,rpm): declare libxdo as runtime dependency

Donut Browser uses libxdo at runtime (loaded via dlopen, not directly
linked), so Tauri's auto-dependency detection misses it. As a result,
the DEB/RPM packages install cleanly but launching the app fails
silently with:

  /usr/bin/donutbrowser: error while loading shared libraries:
  libxdo.so.3: cannot open shared object file: No such file or directory

Declare libxdo3 (Debian/Ubuntu) and libxdo (Fedora/openSUSE) explicitly
in bundle.linux.{deb,rpm}.depends so package managers pull the library
during install.

src-tauri/tauri.conf.json

@@ -42,11 +42,11 @@
     "linux": {
       "deb": {
         "desktopTemplate": "donutbrowser.desktop",
-        "depends": ["xdg-utils"]
+        "depends": ["xdg-utils", "libxdo3"]
       },
       "rpm": {
         "desktopTemplate": "donutbrowser.desktop",
-        "depends": ["xdg-utils"]
+        "depends": ["xdg-utils", "libxdo"]
       },
       "appimage": {
         "files": {