Problem

The TUI markdown renderer (ui-tui/src/components/markdown.tsx) detects GFM pipe tables correctly, but renderTable only produces aligned columns without any border lines — no | separators, no - row dividers. The output looks like plain aligned text, making tables nearly indistinguishable from regular paragraphs, especially in dark terminal themes.

What renderTable currently outputs (conceptual)

  Header1   Header2   Header3       <- amber color
  data      data      data          <- default color
  data      data      data

No box-drawing characters, no pipe separators, no row dividers.

What users expect

Something with visible borders — either Unicode box-drawing or at minimum pipe+dash separators:

  | Header1 | Header2 | Header3 |
  |---------|---------|---------|
  | data    | data    | data    |
  | data    | data    | data    |

Or with Unicode box-drawing:

  ╔════════╦════════╦════════╗
  ║ Header ║ Header ║ Header ║
  ╠════════╬════════╬════════╣
  ║ data   ║ data   ║ data   ║
  ╚════════╩════════╩════════╝

Context

• File: ui-tui/src/components/markdown.tsx, function renderTable
• The function uses Ink Box + Text components with paddingLeft: 2 and column alignment via stringWidth, but draws no borders
• Header row gets t.color.amber, data rows get default color — this is the only visual differentiation
• Telegram had the same problem (PR feat(telegram): auto-wrap markdown tables in code blocks #11794) and solved it by wrapping tables in fenced code blocks. A similar approach could work for TUI, or better yet, add native border rendering

Suggested Fix

Option A: Add Unicode box-drawing borders (configurable via theme)

Option B: Add pipe+dash separators to match GFM rendering

Option C: Wrap detected tables in a styled Ink Box with borderStyle

Option C would leverage Ink's existing border support (borderStyle: "round" | "single" | "double" | "bold") and would be the most consistent with the rest of the TUI's visual style.

Environment

• Hermes version: 2182de55 (latest HEAD)
• Terminal: Windows Terminal (WSL2)
• TUI mode: hermes --tui