table markdown rendering improvement

CLAUDE.md

@@ -168,9 +168,12 @@ UI thread redraws on its own tick (no channel; just the mutex).
 
 ## Gotchas
 
-- `tui-markdown` is pinned `=0.3.5`: later versions use `ratatui-core` (0.30
-  alpha types), incompatible with ratatui 0.29. Its gaps (no tables, literal
-  heading markers) are compensated in `src/markdown.rs`, not by upgrading.
+- `tui-markdown` is pinned `=0.3.5`: 0.3.7+ moved to `ratatui-core` (0.30 alpha
+  types), incompatible with ratatui 0.29 — 0.3.6 is the last 0.29-compatible
+  release, but *no* version (through 0.3.8) enables pulldown-cmark's table
+  extension, so upgrading still wouldn't render tables. Its gaps (no tables,
+  literal heading markers) are compensated in `src/markdown.rs`, not by
+  upgrading.
 - `wezterm-term`/`wezterm-surface` are not on crates.io: pinned to a git rev
   of the wezterm monorepo (keep both revs identical).
 - The compact pane *dynamically frames* Claude Code's input box rather than

src/markdown.rs

@@ -3,9 +3,14 @@
 //! tui-markdown 0.3.5 never enables pulldown-cmark's table extension, so GFM
 //! pipe tables fall through as raw paragraph text, and it keeps the literal
 //! `### ` markers on headings. This module splits table blocks out of the
-//! text, renders them itself (box-drawing borders, width-fitted columns,
-//! word-wrapped cells — matching Claude Code's own table style), routes the
-//! rest through tui-markdown, and strips heading markers from its output.
+//! text, renders them itself (box-drawing borders with a rule between every
+//! row, width-fitted columns, word-wrapped cells), routes the rest through
+//! tui-markdown, and strips heading markers from its output.
+//!
+//! Why not hand tables to a crate: the only tui-markdown still compatible with
+//! ratatui 0.29 is 0.3.6 (0.3.7+ moved to ratatui-core / the 0.30 alpha), and
+//! none of those versions enable pulldown-cmark's table extension — so an
+//! upgrade still wouldn't render tables. This stays the owner of table layout.
 //!
 //! Re-rendered every frame on partial content: a table only renders as a
 //! table once its header + separator row have streamed in, so half-received
@@ -278,7 +283,13 @@ fn render_table<'a>(rows: &[&str], width: u16, out: &mut Vec<Line<'a>>) {
     out.push(border(&widths, '┌', '┬', '┐'));
     push_row(out, &header, &widths, &[Align::Center].repeat(cols));
     out.push(border(&widths, '├', '┼', '┤'));
-    for row in &body {
+    // A rule between every body row, not just under the header: cells wrap to
+    // several lines each, so without internal separators consecutive rows run
+    // together into one unreadable block.
+    for (idx, row) in body.iter().enumerate() {
+        if idx > 0 {
+            out.push(border(&widths, '├', '┼', '┤'));
+        }
         push_row(out, row, &widths, &aligns);
     }
     out.push(border(&widths, '└', '┴', '┘'));
@@ -396,6 +407,24 @@ mod tests {
         );
     }
 
+    #[test]
+    fn body_rows_are_separated_by_a_rule() {
+        let md = "| A | B |\n|---|---|\n| 1 | 2 |\n| 3 | 4 |\n";
+        let got = flat(&render(md, 40));
+        assert_eq!(
+            got,
+            vec![
+                "┌───┬───┐",
+                "│ A │ B │",
+                "├───┼───┤",
+                "│ 1 │ 2 │",
+                "├───┼───┤",
+                "│ 3 │ 4 │",
+                "└───┴───┘",
+            ]
+        );
+    }
+
     #[test]
     fn narrow_table_wraps_cells_within_width() {
         let md = "| Option | Notes |\n|---|---|\n| Delayed data | Far fewer licensing restrictions apply here |\n";