SCRUM-5928 fix missing attributes: nucleotide change, cross references

[cmpich]

No description provided.

[claude]

Code Review

Single file changed: VariantSummaryCuration.jsx — adds fallback logic for three variant attributes that can be missing from the primary data source.

Changes reviewed:

1. crossReferences fallback (lines 32-35): Falls back to allele.dataProviderCrossReference when variant-level cross references are empty. The [...].filter(Boolean) guard correctly handles the case where the allele field is also missing, producing an empty array that the downstream crossReferences.length check handles properly.

2. nucleotideChange fallback chain (lines 50-53): Three-tier fallback: direct field → constructed from ref/var sequences → regex extraction from HGVS genomic notation. The regex /g\.\d+(?:_\d+)?(.+)$/ correctly captures the change portion of standard HGVS g. notation (e.g., A>G from g.12345A>G, del from g.12345del).

3. hgvsC / hgvsP fallback (lines 59-64): Falls back to mapping predictedVariantConsequences when direct fields are absent. The .filter(Boolean) strips null/undefined entries. An empty result array correctly short-circuits at the hgvsC.length / hgvsP.length render guards (lines 154, 157).

The predictedVariantConsequences extraction was correctly hoisted above its new consumers. All fallback paths handle undefined/null/empty inputs without risk of runtime errors.

No issues found — looks good.