feat: mitigate MathJax formula warnings

tests/test_quality.py

@@ -6,6 +6,7 @@ from pdf2md.ir import WarningCode, WarningSeverity
 from pdf2md.quality import (
     MathCheckerUnavailable,
     MathCheckResult,
+    check_math_renderability_details,
     check_asset_links,
     check_math_renderability,
     extract_math_expressions,
@@ -71,6 +72,20 @@ def test_math_render_failures_are_aggregated_with_fake_checker() -> None:
     assert "bad_math failed" in result.warnings[0].message
 
 
+def test_math_renderability_details_include_failed_expression_records() -> None:
+    def checker(body: str) -> MathCheckResult:
+        return MathCheckResult(ok="bad" not in body, message=f"{body} failed")
+
+    result = check_math_renderability_details("$x_i$\n\n$$\nbad_math\n$$", checker)
+
+    assert result.quality.math_render_error_count == 1
+    assert len(result.failures) == 1
+    assert result.failures[0].expression.index == 1
+    assert result.failures[0].expression.body == "bad_math"
+    assert result.failures[0].expression.display is True
+    assert result.failures[0].message == "bad_math failed"
+
+
 def test_math_extraction_records_display_mode_and_markdown_spans() -> None:
     markdown = "Inline $x_i^2$ before\n\n$$\n\\frac{1}{2}\n$$\n"