fix(deep-link): preserve XDG registration ownership and report failures (#3585)

* fix(deep-link): honor XDG failures and unregister associations

* test(deep-link): isolate other application handlers

* chore: satisfy release metadata and test header checks

* fix(deep-link): gate XDG helpers to Linux

The plugin only supports Linux, so FreeBSD builds warned about dead code.

* refactor(deep-link): add run_command helper

Share the spawn, status check and logging for XDG commands.

* refactor(deep-link): share desktop file list helpers

register and unregister now edit MimeType lists the same way.

* fix(deep-link): keep desktop file quoting on register

Parse raw values so a quoted Exec matches and isn't rewritten each time.

* fix(deep-link): clean mimeapps.list first on unregister

A failing update-desktop-database no longer leaves the app as the default.

* fix(deep-link): keep mimeapps.list comments on unregister

Edit it line by line instead of re-serializing it through rust-ini.

* fix(deep-link): skip cache refresh when nothing to unregister

Only run update-desktop-database if the desktop file changed or the cache still lists the app.

* fix(deep-link): treat no default handler as unregistered

xdg-mime exits with 4 on KDE and LXQt when no handler is set.

* fix(deep-link): tolerate padded xdg-mime query output

Compare the trimmed first line instead of the raw output.

* test(deep-link): run XDG tests in CI

Drop #[ignore], skip when the tools are missing, and install them on Linux CI.

---------

Co-authored-by: Lucas Nogueira <lucas@tauri.app>

.github/workflows/test-rust.yml

@@ -112,6 +112,8 @@ jobs:
         run: |
           sudo apt-get update
           sudo apt-get install -y libwebkit2gtk-4.0-dev libwebkit2gtk-4.1-dev dbus
+          # the deep-link tests drive the real XDG tools
+          sudo apt-get install -y xdg-utils desktop-file-utils
 
       - uses: dtolnay/rust-toolchain@1.90
         with: