Animated filter: server-side filetype tag for full results

Danbooru/e621: filetype:gif,mp4,webm,zip
Gelbooru/Moebooru: animated tag
Client-side filter kept as fallback safety net.

booru_viewer/gui/app.py

@@ -719,6 +719,15 @@ class BooruApp(QMainWindow):
         if self._min_score > 0:
             parts.append(f"score:>={self._min_score}")
 
+        # Animated filter — server-side where supported
+        if self._animated_only.isChecked():
+            if api in ("danbooru", "e621"):
+                parts.append("filetype:gif,mp4,webm,zip")
+            elif api == "gelbooru":
+                parts.append("animated")
+            else:
+                parts.append("animated")
+
         return " ".join(parts)
 
     def _do_search(self) -> None: