fix: hide quality slider and skip re-compression for GIF-to-MP4

The GIF converter already produces a well-compressed H.264 MP4, so
re-compressing via VideoCompressionHelper is wasteful and can inflate
file size. Hide the quality slider in the upload UI when GIF-to-MP4
is enabled and skip the video compression step in MediaCompressor.

https://claude.ai/code/session_018sKCM3VNWtfPMZSYVWWD4w

amethyst/src/main/java/com/vitorpamplona/amethyst/service/uploads/MediaCompressor.kt

@@ -51,21 +51,12 @@ class MediaCompressor {
     ): MediaCompressorResult {
         checkNotInMainThread()
 
-        // Convert GIF to MP4 if requested (before quality check, since this is a format conversion)
+        // Convert GIF to MP4 if requested. The GIF converter already produces a well-compressed
+        // H.264 MP4 so no additional video compression step is needed.
         if (convertGifToMp4 && contentType?.contains("gif", ignoreCase = true) == true) {
             Log.d("MediaCompressor") { "Converting GIF to MP4" }
             val converted = GifToMp4Converter.convert(uri, applicationContext)
             if (converted != null) {
-                // Optionally compress the resulting video
-                if (mediaQuality != CompressorQuality.UNCOMPRESSED) {
-                    return VideoCompressionHelper.compressVideo(
-                        converted.uri,
-                        converted.contentType,
-                        applicationContext,
-                        mediaQuality,
-                        useH265,
-                    )
-                }
                 return converted
             }
             Log.w("MediaCompressor") { "GIF to MP4 conversion failed, uploading as original GIF" }

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/note/creators/uploads/ImageVideoDescription.kt

@@ -271,7 +271,7 @@ fun ImageVideoDescription(
 
             val firstMedia = uris.first().media
 
-            if (firstMedia.isVideo() == true || firstMedia.isImage() == true) {
+            if ((firstMedia.isVideo() == true || firstMedia.isImage() == true) && !convertGifToMp4) {
                 Row(
                     verticalAlignment = Alignment.CenterVertically,
                     modifier =