feat: data_models 扩展 MixedParagraph/MixedSheet（段落容器）

tests/test_excel_parser.py

@@ -57,3 +57,27 @@ def test_parse_attaches_strikethrough_formatting(tmp_path):
     cv = result.tables[0].rows[0]["機能ID"]
     assert cv.formatting is not None
     assert cv.formatting.strikethrough is True
+
+
+from genesis.data_models import MixedParagraph, MixedSheet
+from genesis.parsers.excel_parser import ExcelParseResult
+
+
+def test_excel_parse_result_has_mixed_default():
+    r = ExcelParseResult(file_name="f.xlsx")
+    assert r.mixed == []
+
+
+def test_mixed_paragraph_defaults():
+    p = MixedParagraph(kind="table")
+    assert p.table is None
+    assert p.text is None
+    assert p.source_range is None
+
+
+def test_mixed_sheet_holds_paragraphs():
+    p1 = MixedParagraph(kind="table")
+    p2 = MixedParagraph(kind="free_text", text="备注")
+    ms = MixedSheet(name="混合", paragraphs=[p1, p2])
+    assert ms.name == "混合"
+    assert [p.kind for p in ms.paragraphs] == ["table", "free_text"]