`<Tab>` / `<S-Tab>` in insert mode navigate between table cells when
the cursor is on a `|…|` row, otherwise they pass through to their
default insert-mode behaviour (literal tab / shift-tab). Same
`<expr>`-mapping idiom as Cluster 5's smart_return.
<Tab> next cell; creates a fresh row below if past the last cell
<S-Tab> previous cell; no-op past the first
Cursor lands immediately after the destination cell's leading `|`,
matching upstream vimwiki's `vimwiki#tbl#go_*_cell` behaviour.
Both Lua and VimL counterparts wired into ftplugin's existing
table_editing block (gated alongside `gqq`/`<A-Left>`).
Tests: 4 new in scripts/test-keymaps.lua — next cell, new-row
overflow, previous cell, and pass-through outside a table.
Gates: 421 Rust / 39 Neovim / 12 Vim.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
gffranco
2562a046db