* feat(preview): add `max_file_size` config to skip large file previews
Problem: previewing large files (e.g. 500 MB logs, binaries) loads them
into a buffer and can freeze or OOM Neovim. `disable_preview` only
receives the filename, so users cannot gate on file size.
Solution: add `preview_win.max_file_size` (number, MB, default 10). In
`open_preview`, check `entry.meta.stat.size` and fall back to
`vim.uv.fs_stat` when the cached stat is absent. If the file exceeds
the limit and a preview window is already open, render "File too large
to preview" in it; if not, emit a WARN notify and return early. The
cursor-moved auto-update path only fires when a window already exists,
so no flag threading is needed to distinguish explicit from implicit.
Based on: stevearc/oil.nvim#213
* feat(view): add `show_hidden_when_empty` for hidden-only directories
Problem: with `show_hidden = false`, a directory containing only
dotfiles renders as just `..`, giving no indication that entries exist.
Solution: add `view_options.show_hidden_when_empty` (boolean, default
false). After the main filter loop in `render_buffer`, if the option is
set and `#line_table <= 1`, iterate `entry_list` again and render any
entry not matched by `is_always_hidden`, using `is_hidden = true` so
they render with the dimmed hidden style.
Based on: stevearc/oil.nvim#473
* docs(upstream): fix formatting
* docs(upstream): update #213 and #473 with PR and commit links