feat(normalizer): xlsx ingest + header mapping

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

tools/import-normalizer/tests/test_ingest.py

@@ -0,0 +1,36 @@
+import datetime
+import openpyxl
+import pytest
+import ingest
+
+def _make_workbook(tmp_path, sheet_name, rows):
+    wb = openpyxl.Workbook()
+    ws = wb.active
+    ws.title = sheet_name
+    for r in rows:
+        ws.append(r)
+    path = tmp_path / "wb.xlsx"
+    wb.save(path)
+    return path
+
+def test_read_sheet_converts_cells(tmp_path):
+    path = _make_workbook(tmp_path, "S", [
+        ["Index", "Datum"],
+        ["W-0001", datetime.datetime(1888, 2, 15)],
+        ["W-0002", 1],
+    ])
+    rows = ingest.read_sheet(path, "S")
+    assert rows[0] == ["Index", "Datum"]
+    assert rows[1] == ["W-0001", "1888-02-15"]   # Excel date -> ISO string
+    assert rows[2] == ["W-0002", "1"]            # integer -> plain string
+
+def test_build_header_map_collapses_whitespace_and_case():
+    header = ["Index", "Datum  des Briefes", "EmpfängerIn", "Mystery"]
+    field_map = {"index": "index", "datum des briefes": "date", "empfängerin": "receivers"}
+    fields, unknown = ingest.build_header_map(header, field_map, required={"index"})
+    assert fields == {"index": 0, "date": 1, "receivers": 2}
+    assert unknown == ["Mystery"]
+
+def test_build_header_map_missing_required_raises():
+    with pytest.raises(ValueError, match="index"):
+        ingest.build_header_map(["Box", "Ort"], {"box": "box", "ort": "location"}, required={"index"})