Fix phase field initialization for ncRNA genes without CDS

When parsing genes with mRNA/transcript type but no CDS features (ncRNA),
the phase field was not being appended to the results dictionary, causing
a length mismatch error in validate_models().

This fix adds results['phase'].append([]) for ncRNA genes to match the
pattern used for other gene types, ensuring all required fields have
consistent lengths.

Fixes 5 failing tests related to parsing genes without CDS features.

Author: Jon Palmer

gfftk/gff.py

@@ -1934,6 +1934,7 @@ def validate_and_translate_models(
                 results["codon_start"].append(None)
                 results["partialStart"].append(None)
                 results["partialStop"].append(None)
+                results["phase"].append([])
             else:
                 # Sort CDS and phase together to maintain correspondence
                 results["type"].append("mRNA")