Feature request: Box-drawing character borders for table rendering

[bquenin]

Description

The current plugin outputs tables using standard markdown pipe syntax (| cell |). While this works well and aligns columns correctly, using Unicode box-drawing characters produces a much nicer visual result in the terminal.

Proposal

Replace (or optionally support) pipe-based borders with box-drawing characters.

Current output:

| Feature | Status | Notes |
|---------|--------|-------|
| Bold    | Active | v2.0  |

Proposed output:

┌─────────┬────────┬───────┐
│ Feature │ Status │ Notes │
├─────────┼────────┼───────┤
│ Bold    │ Active │ v2.0  │
└─────────┴────────┴───────┘

Screenshot

Here's what it looks like in OpenCode with concealment mode enabled, including bold, italic, strikethrough, inline code, and links:

Notes

• Concealment mode compatibility is preserved — width calculations are unchanged, only the frame characters differ
• Alignment (left/center/right) works correctly
• The trade-off is that the output is no longer valid markdown for copy-paste. This could be addressed by making it a configurable option ("pipe" vs "box")
• Proof of concept fork: https://github.com/bquenin/opencode-md-table-formatter