style: apply gofmt across Go sources

Repo-wide gofmt sweep: const-block alignment, doc-comment spacing,
statement-after-brace fix in media.go, trailing blank lines. No
semantic changes — whitespace-insensitive diff is empty for every
file in this commit.

cmd/server/tests/audio_speed_test.go

@@ -98,7 +98,7 @@ func TestAudioPlaybackSpeed(t *testing.T) {
 		defer closer()
 		require.Equal(t, http.StatusOK, resp.StatusCode)
 		var data struct {
-			PlaybackSpeed       float64 `json:"playback_speed"`
+			PlaybackSpeed        float64 `json:"playback_speed"`
 			DefaultPlaybackSpeed float64 `json:"default_playback_speed"`
 		}
 		require.NoError(t, json.NewDecoder(resp.Body).Decode(&data))