Implemented full markdown table support:
- Parse tables with headers, rows, and alignment.
- Render tables as a grid when width permits, falling back to a stacked layout for narrow widths.
- Added helper structs (`ParsedTable`, `TableAlignment`) and functions for splitting rows, parsing alignments, column width constraints, cell alignment, and wrapping.
- Integrated table rendering into `render_markdown_lines`.
- Added unit tests for grid rendering and narrow fallback behavior.
vikingowl
96e0436d43