yoda: prefer cosmic-yoterm over upstream cosmic-term in terminal fallback

mime_app::MimeAppCache::terminal() hardcoded "com.system76.CosmicTerm"
as the only non-xdg-default fallback. On a yoda stack the relevant
terminal is our fork cosmic-yoterm (desktop id com.aditua.CosmicYoterm),
so we add it first in preference_order. xdg-mime default still wins
when set — this just covers the case where it isn't.

Fixes "Open in terminal" launching Konsole (or first random terminal in
apps list) instead of cosmic-yoterm when xdg-mime default is unset or
points to something else.

src/mime_app.rs

@@ -399,9 +399,12 @@ impl MimeAppCache {
         // The current approach works but might not adhere to the spec (yet)
 
         // Look for and return preferred terminals
-        //TODO: fallback order beyond cosmic-term?
-
-        let mut preference_order = vec!["com.system76.CosmicTerm".to_string()];
+        // Yoda: cosmic-yoterm (our fork) wins over upstream cosmic-term if both
+        // are installed — useful when xdg-mime default is not set.
+        let mut preference_order = vec![
+            "com.aditua.CosmicYoterm".to_string(),
+            "com.system76.CosmicTerm".to_string(),
+        ];
 
         if let Some(id) = self.get_default_terminal() {
             preference_order.insert(0, id);