Remove textLength attribute - fixes cursor positioning issues

The textLength with lengthAdjust='spacing' approach was causing visual
positioning problems. While x coordinates were calculated correctly,
the browser's spacing adjustments shifted subsequent text visually,
causing cursor and text to appear offset.

Removed textLength entirely. Accepting slight visual gaps in horizontal
box-drawing lines is preferable to cursor misalignment.

Version bump to 0.3.10

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "textual-webterm"
-version = "0.3.9"
+version = "0.3.10"
 description = "Serve terminal sessions over the web"
 authors = ["Will McGugan <will@textualize.io>"]
 license = "MIT"

src/textual_webterm/svg_exporter.py

@@ -222,13 +222,10 @@ def render_terminal_svg(
             if classes:
                 attrs.append(f'class="{" ".join(classes)}"')
 
-            # For horizontal box-drawing spans, use textLength to ensure correct width
-            # This prevents gaps caused by font rendering of ─ being narrower than char_width
-            # Use "mostly" check to handle occasional corrupted chars (like U+FFFD)
-            if _is_mostly_horizontal_box_drawing(text) and len(text) > 1:
-                span_width = columns * char_width
-                attrs.append(f'textLength="{span_width:.1f}"')
-                attrs.append('lengthAdjust="spacing"')
+            # Note: textLength with lengthAdjust="spacing" was tried but causes
+            # visual positioning issues. The browser adds spacing between chars
+            # which shifts subsequent text visually even though x coords are correct.
+            # Accepting slight gaps in horizontal lines is preferable to cursor misalignment.
 
             parts.append(f'<tspan {" ".join(attrs)}>{_escape_xml(text)}</tspan>')
             x += columns * char_width

tests/test_svg_exporter.py

@@ -829,8 +829,8 @@ class TestEdgeCases:
         assert "─" in svg
         assert "┐" in svg
 
-    def test_horizontal_lines_use_textlength(self) -> None:
-        """Horizontal line spans use textLength for correct width."""
+    def test_horizontal_lines_render_without_textlength(self) -> None:
+        """Horizontal lines render without textLength (removed due to positioning issues)."""
         buffer = [[
             self._char("╭"),
             self._char("─"),
@@ -839,9 +839,11 @@ class TestEdgeCases:
             self._char("╮"),
         ]]
         svg = render_terminal_svg(buffer, width=5, height=1)
-        # Horizontal lines should have textLength attribute
-        assert 'textLength="24.0"' in svg
-        assert 'lengthAdjust="spacing"' in svg
+        # Horizontal lines should NOT have textLength (causes visual offset issues)
+        assert 'textLength=' not in svg
+        assert 'lengthAdjust=' not in svg
+        # But the characters should still be present
+        assert "─" in svg or "───" in svg
 
     def test_ansi_bright_colors(self) -> None:
         """All bright ANSI colors render."""