pgx_cn: PFB as float64 for the BAF evidence (mypy)

Co-Authored-By: Claude Opus 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01814GKVzZVL3FuF3DeiZXhv

src/simurg/pipeline/pgx_cn.py

@@ -412,7 +412,7 @@ def call_sample_regions(
         if baf is not None:
             sel = model.region_sel(r.name)
             rb = baf[sel]
-            pf = model.probe_pfb[sel] if model.probe_pfb is not None else None
+            pf = model.probe_pfb[sel].astype(np.float64) if model.probe_pfb is not None else None
             if pf is not None:
                 rb = np.where(np.isfinite(pf) & (pf > 0.01) & (pf < 0.99), rb, np.nan)  # informative SNPs only
             n_snp = int(np.isfinite(rb).sum())