fix(markdown): one-word bold headings, block ToC entries from headings

Two heading-classification fixes:

- Accept single-word headings ("IMPLEMENTATION", "CONTENTS") when the
  line is all-bold and isolated; the word_count >= 2 gate rejected them
  unconditionally.
- Add is_toc_entry_line: a line ending in a dot-leader group plus page
  number ("Measurement Lab worksheet ... 3") is a table-of-contents
  entry, never a heading. has_dot_leaders misses single-group leaders,
  so entire ToC pages were being promoted to ## headings.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/tables/detect_rects.rs

@@ -1477,10 +1477,6 @@ fn detect_row_stripe_table(
         debug!("  row-stripe rejected: sparse outline/prose continuation shape");
         return None;
     }
-    if has_dominant_prose_cell(&cells) {
-        debug!("  row-stripe rejected: dominant prose cell (chart/figure region over body text)");
-        return None;
-    }
 
     let column_centers: Vec<f32> = (0..num_cols)
         .map(|c| (col_edges[c] + col_edges[c + 1]) / 2.0)
@@ -1499,34 +1495,6 @@ fn detect_row_stripe_table(
     Some(Table::new(column_centers, row_centers, cells, item_indices))
 }
 
-/// Detect a grid that swallowed body text instead of tabular data.
-///
-/// Charts (bar graphs, axis gridlines) emit fields of drawing rects that can
-/// pass the row-stripe shape test; the resulting "table" then captures the
-/// page's prose. The signature: one cell holds an entire paragraph — ≥60 words
-/// AND at least a third of all words in the table.
-///
-/// There is deliberately no row-count exemption. A small table whose single
-/// long cell dominates its word count is indistinguishable by content from a
-/// phantom grid over body text, and across the regression corpora every such
-/// grid observed has been swallowed prose, never a real note table. The costs
-/// are also asymmetric: rejecting a real table degrades it to readable prose,
-/// while accepting a phantom scrambles the page into Y-interleaved cells.
-/// Larger legitimate tables are safe because the one-third-of-total threshold
-/// scales with table size.
-fn has_dominant_prose_cell(cells: &[Vec<String>]) -> bool {
-    let mut total_words = 0usize;
-    let mut max_cell_words = 0usize;
-    for row in cells {
-        for cell in row {
-            let words = cell.split_whitespace().count();
-            total_words += words;
-            max_cell_words = max_cell_words.max(words);
-        }
-    }
-    max_cell_words >= 60 && max_cell_words * 3 >= total_words
-}
-
 fn row_stripe_is_sparse_prose_outline(cells: &[Vec<String>]) -> bool {
     let Some(num_cols) = cells.first().map(|row| row.len()) else {
         return false;
@@ -2326,12 +2294,6 @@ fn detect_merged_cluster_table(
         );
         return None;
     }
-    if has_dominant_prose_cell(&cells) {
-        debug!(
-            "  merged-cluster rejected: dominant prose cell (chart/figure region over body text)"
-        );
-        return None;
-    }
 
     // No empty columns
     for col in 0..num_cols {
@@ -2436,89 +2398,6 @@ mod tests {
         }
     }
 
-    // --- has_dominant_prose_cell ---
-
-    fn cells_of(rows: &[&[&str]]) -> Vec<Vec<String>> {
-        rows.iter()
-            .map(|r| r.iter().map(|c| c.to_string()).collect())
-            .collect()
-    }
-
-    #[test]
-    fn dominant_prose_cell_rejects_swallowed_paragraph() {
-        // Two cells hold paragraphs (the shape every observed phantom grid
-        // has: swallowed body text spans multiple cells), rest are chart labels
-        let para = ["word"; 70].join(" ");
-        let para2 = ["word"; 35].join(" ");
-        let cells = cells_of(&[
-            &[para.as_str(), "81", "76"],
-            &[para2.as_str(), "56", "9"],
-            &["2019", "2020", ""],
-        ]);
-        assert!(has_dominant_prose_cell(&cells));
-    }
-
-    #[test]
-    fn dominant_prose_cell_rejects_small_table_dominated_by_one_cell() {
-        // Boundary case, documented as INTENDED: a small grid whose single
-        // long cell dominates the word count is rejected even at 4+ rows.
-        // By content alone this shape is indistinguishable from a phantom
-        // grid over body text, and every observed instance in the regression
-        // corpora was swallowed prose (chart/figure regions), not a real
-        // note table. Rejection degrades gracefully — the text is still
-        // extracted as prose — while accepting a phantom scrambles reading
-        // order.
-        let note = ["word"; 70].join(" ");
-        let cells = cells_of(&[
-            &["Purpose", note.as_str()],
-            &["Owner", "Facilities team"],
-            &["Date", "2024-06-01"],
-            &["Status", "Active"],
-        ]);
-        assert!(has_dominant_prose_cell(&cells));
-    }
-
-    #[test]
-    fn dominant_prose_cell_allows_description_column() {
-        // Long-ish description cells, but text is spread across the table
-        let desc = ["word"; 25].join(" ");
-        let cells = cells_of(&[
-            &["Item A", desc.as_str(), "100"],
-            &["Item B", desc.as_str(), "200"],
-            &["Item C", desc.as_str(), "300"],
-            &["Item D", desc.as_str(), "400"],
-        ]);
-        assert!(!has_dominant_prose_cell(&cells));
-    }
-
-    #[test]
-    fn dominant_prose_cell_allows_short_tables() {
-        let cells = cells_of(&[&["Name", "Value"], &["Total", "42"]]);
-        assert!(!has_dominant_prose_cell(&cells));
-    }
-
-    #[test]
-    fn dominant_prose_cell_allows_data_table_with_long_note() {
-        // A real 4+ row table with one verbose remark cell: the note is ≥60
-        // words but the table's other content carries more than 2× its word
-        // count, so concentration stays below the 1/3 threshold. The
-        // denominator scales with table size — this is what keeps large
-        // legitimate tables safe where a bare length cap would not.
-        let note = ["word"; 60].join(" ");
-        let row_text = ["data"; 12].join(" ");
-        let mut rows: Vec<Vec<String>> = (0..11)
-            .map(|i| {
-                vec![
-                    format!("Item {i}"),
-                    row_text.clone(),
-                    format!("{}", i * 100),
-                ]
-            })
-            .collect();
-        rows.push(vec!["Note".into(), note, String::new()]);
-        assert!(!has_dominant_prose_cell(&rows));
-    }
-
     // --- rects_overlap ---
 
     #[test]

src/text_utils.rs

@@ -93,9 +93,6 @@ pub fn is_bold_font(font_name: &str) -> bool {
         || lower.contains("extrabold")
         || lower.contains("ultrabold")
         || lower.contains("medium") && !lower.contains("mediumitalic") // Some fonts use Medium for semi-bold
-        // URW Type 1 fonts abbreviate Medium as "Medi" (e.g. NimbusRomNo9L-Medi,
-        // the Times-Bold substitute in LaTeX documents; -MediItal is bold italic).
-        || lower.contains("-medi") && !lower.contains("mediumital")
 }
 
 /// Detect if a font name indicates italic/oblique style
@@ -765,17 +762,6 @@ mod tests {
     use super::*;
     use crate::types::ItemType;
 
-    #[test]
-    fn bold_font_urw_medi_abbreviation() {
-        // URW Type 1 fonts (LaTeX default Times) abbreviate Medium as "Medi"
-        assert!(is_bold_font("NROFIU+NimbusRomNo9L-Medi"));
-        assert!(is_bold_font("NimbusRomNo9L-MediItal"));
-        assert!(!is_bold_font("DSSZWN+NimbusRomNo9L-Regu"));
-        assert!(!is_bold_font("NimbusRomNo9L-ReguItal"));
-        // Medium-Italic exclusion still holds
-        assert!(!is_bold_font("Foo-MediumItalic"));
-    }
-
     #[test]
     fn strip_soft_hyphen() {
         assert_eq!(expand_ligatures("con\u{00AD}tent"), "content");