feat(quality): clean LaTeX accents/ties + word-boundary truncation in section titles

Polish _clean_title for R-F: strip accent/escape macros (backslash-quote o to o, backslash-amp), convert tilde ties to spaces, and truncate at a word boundary so stored section titles read cleanly (mobius invariance, colin de verdiere). Tests added; ruff + mypy clean.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tests/quality/test_quality.py

@@ -257,6 +257,19 @@ class TestCleanTitle:
     def test_collapses_and_lowercases(self):
         assert _clean_title("  Rigidity   Results  ") == "rigidity results"
 
+    def test_strips_accent_macros(self):
+        assert _clean_title(r"M\"obius Invariance") == "mobius invariance"
+
+    def test_strips_ties_and_accents(self):
+        assert _clean_title(r"Colin~de~Verdi\`ere") == "colin de verdiere"
+
+    def test_truncates_at_word_boundary(self):
+        long = "alpha beta gamma delta epsilon zeta eta theta iota kappa lambda mu nu omega"
+        out = _clean_title(long)
+        assert len(out) <= 60
+        assert not out.endswith(" ")
+        assert long.lower().startswith(out)  # whole words from the start, no partial tail
+
 
 class TestSectionLabel:
     def test_title_maps_to_controlled_bucket(self):