style: gofmt fixes across api package

CI's golangci-lint run flagged three files; two pre-existed this
branch but the Plan 3 seedTrackWithFile struct-literal alignment
is new. Applying gofmt across all three keeps the lint baseline clean.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

internal/api/convert_test.go

@@ -153,11 +153,11 @@ func TestTrackRefFromNilPositions(t *testing.T) {
 
 func TestParsePaging(t *testing.T) {
 	tests := []struct {
-		name      string
-		query     url.Values
-		wantLimit int
+		name       string
+		query      url.Values
+		wantLimit  int
 		wantOffset int
-		wantErr   bool
+		wantErr    bool
 	}{
 		{
 			name:       "default (empty values)",