fix(writer): 防静默丢章告警 + 占位符正则宽容化（大小写/全角冒号）

tests/test_word_template_parser.py

@@ -104,3 +104,29 @@ def test_parse_styles_collected(tmp_path):
     assert "Heading 1" in result.styles["used"]
     assert "Normal" in result.styles["used"]
     assert "Heading 1" in result.styles["defined"]
+
+
+def test_parse_extracts_placeholder_case_insensitive(tmp_path):
+    # 宽容：键名大小写不敏感 → 归一为小写 section:id
+    doc = new_document()
+    doc.add_paragraph("{{Section:2}}")
+    path = save_document(tmp_path, doc)
+
+    result = WordTemplateParser().parse(path)
+
+    assert result.placeholders == {"section:2": "{{Section:2}}"}
+    ph = [s for s in result.sections if s.type == "placeholder"]
+    assert [s.name for s in ph] == ["section:2"]
+
+
+def test_parse_extracts_placeholder_fullwidth_colon(tmp_path):
+    # 宽容：全角冒号（：）也视为分隔符 → 归一为半角 section:id
+    doc = new_document()
+    doc.add_paragraph("{{section：2}}")
+    path = save_document(tmp_path, doc)
+
+    result = WordTemplateParser().parse(path)
+
+    assert result.placeholders == {"section:2": "{{section：2}}"}
+    ph = [s for s in result.sections if s.type == "placeholder"]
+    assert [s.name for s in ph] == ["section:2"]