fix(tui): support copy mode over markdown tables

[shaheislam]

Problem

In copy mode, visual-line/char/block selection over markdown tables copied nothing or showed only a 1-character placeholder highlight. Tables render as TextTableRenderable, which exposes neither plainText nor lineInfo, so copy-mode's renderable walk skipped them.

Fix

• Make copy-mode table-aware and extract per-display-line text from table cells.
• Keep linewise table yanks as tab-separated cells without borders, matching the table's own selection format.
• Skip table border rows for linewise yanks.
• Use rendered table geometry for highlights, cursor movement, stick/preferred-column behavior, search, word motions, and char/block selection.

Before

After

Tests

• Added copy-mode table regressions for TSV yank, border skipping, rendered highlight geometry, cursor movement, vertical preferred-column preservation, char visual yank, and wrapped cell lines.
• bun test test/cli/tui/vim-motions.test.ts from packages/tui: 731 pass
• bun typecheck from packages/tui: pass

[shaheislam]

One for review when you get a moment :D @leohenon

[leohenon]

I noticed charwise table selections include non copyable separator rows as blank lines. Can we filter rowCopyable(row, cache) here, and in the block visual path above, matching the linewise behavior?

[shaheislam]

Done thanks @leohenon

[leohenon]

I just added a comment for the table internals, and a columnOffsets guard in the table adapter. Thanks for tackling this, its a solid improvement.