PGx star alleles: pgx star-allele call (PGX-011..021), probe masks vs 1000G, GeT-RM validation (K-029)

- simurg/pgx/star.py: solver-free diplotype enumeration incl. CN forms (deletion, xN), wildcards, array-equivalence
  classes, raw_score/score with CPIC frequency priors; calibrated error model (spec PGX-012 amended).
- pipeline/pgx_star.py: DB gene models, SNV + PGx CN VCF evidence, masks, diplotype_summary.tsv + pgx_calls.json.
- scripts/pgx: derive_masks.py (array vs 1000G 30x over HTTPS, GS calibration), getrm_truth.py,
  validate_star_getrm.py.
- GSA v4 PGx demo vs GeT-RM (16 CEPH): 100/109 gene calls; CYP2D6/2C19/2C9 41/45 (docs/validation/V2_pgx_star.md).

src/simurg/core/errors.py

@@ -171,6 +171,9 @@ CATALOGUE: dict[str, MessageDef] = dict(
         _m("W_PGX_NO_ALT_CONTIG", "warning", "FASTA lacks a contig carrying a PGx region; REF written as N", "IN-062"),
         _m("W_PGX_BATCH_COMPOSITION", "warning", "Batch spans several lots/batches or > 14 days of scans", "PCN-006"),
         _m("E_PGX_CN_FAILED", "error", "PGx CN calling failed for the sample", "PCN-002"),
+        _m("E_PGX_CN_MISSING", "error", "A sample has no PGx CN VCF (give --no-cn to run without)", "PGX-011"),
+        _m("E_PGX_VCF_UNINDEXED", "error", "SNV VCFs for PGx must be bgzipped and indexed", "PGX-011"),
+        _m("E_PGX_VCF_UNSUITABLE", "error", "SNV VCF unsuitable for PGx (squashing/locus filters/foreign)", "PGX-011"),
         _m("E_PGX_SOURCE", "error", "PGx source tables missing; run scripts/pgx/fetch_sources.sh", "PGX-001"),
         # --- methylation control QC (MET-001 .. MET-018) -------------------------------------------------
         _m("E_METH_NO_ASSAY", "error", "Probe section not found", "MET-002"),