P4 validated on 2141 vendor GTCs; legacy AutoCall 1.6.2 preset

- vendor comparison (1000 Genomes Omni2.5, AutoCall 1.6.2.2): every
  computed field identical in 2138/2141 samples; the 3 others trace back
  to the single-locus raw-intensity rule (K-009); sex rule 1 matches all
- AutoCall 1.6.2.x leaves GC10/GC50/#calls/#no-calls at 0 in GTC v3:
  new `--preset autocall-1.6.2` (1.1.2 normalization, sex rule 1, GTC v3,
  legacy statistics); the sample summary keeps the real statistics
- NaN sign canonicalised to the x86 pattern (K-014); report P4.md

tests/unit/test_genotype.py

@@ -233,3 +233,25 @@ def test_cluster_alignment_errors(tmp_path: Path) -> None:
     assert e.value.code == "E_EGT_MANIFEST_MISMATCH"
     c = align_clusters(read_egt(tmp_path / "small.egt"), read_bpm(f["bpm"]), allow_missing=True)
     assert int(c.present.sum()) == 1
+
+
+def test_legacy_preset(tmp_path: Path) -> None:
+    from simurg.cli.main import app
+
+    f = _synthetic_run(tmp_path)
+    out = tmp_path / "legacy"
+    r = CliRunner().invoke(app, ["genotype", "--quiet", "--bpm", str(f["bpm"]), "--egt", str(f["egt"]),
+                                 "--idats", str(f["idats"]), "--out", str(out), "--threads", "1",
+                                 "--preset", "autocall-1.6.2"])
+    assert r.exit_code == 0, r.output
+    gtc = next(out.rglob("*.gtc"))
+    g = read_gtc(gtc)
+    assert g.version == 3 and g.gc10 == 0 and g.num_calls == 0 and g.gc50 == 0  # vendor 1.6.2.x conventions
+    summary = json.loads((out / "sample_summary.json").read_text())
+    s0 = summary["samples"][0]
+    assert s0["n_calls"] > 0 and s0["gc10"] > 0  # the summary still reports the real statistics
+    run = json.loads((out / "run_manifest.json").read_text())
+    assert run["effective_options"]["effective_norm_version"]["value"] == "1.1.2"
+    bad = CliRunner().invoke(app, ["genotype", "--bpm", str(f["bpm"]), "--egt", str(f["egt"]), "--idats",
+                                   str(f["idats"]), "--out", str(tmp_path / "x"), "--preset", "nope"])
+    assert bad.exit_code == 2