fix(file_history): keep collapsed entries folded when highlighting a file row - #323

Problem

In the file history panel, highlight_item expands a collapsed commit entry just to land the cursor on one of its file rows:

if entry.folded then
    entry.folded = false
    self:render()
    self:redraw()
end
target_row = comp_struct.comp.lstart + i + 1

This makes any navigation that calls highlight_item (e.g. select_next_entry via <tab>, and the layout-swap rebuild path open() -> highlight_item when jumping between commits of different layouts, such as M -> A) silently re-expand entries the user explicitly collapsed with h.

Expected

Collapsing and expanding are explicit user actions (l / h). Cursor placement must not change fold state. This is also what _restore_state already guarantees on history rebuilds (update_entries), so the two rebuild paths now behave consistently.

Fix

Park the cursor on the entry row instead of expanding the entry:

if self.single_file or entry.folded then
    target_row = comp_struct.comp.lstart + 1
else
    target_row = comp_struct.comp.lstart + i + 1
end

Note on behaviour direction

The diff-view file panel's highlight_file deliberately expands collapsed directories to keep the active file visible. This change takes the opposite stance for the history panel: fold state is preserved on cursor placement, consistent with _restore_state. Happy to gate this behind a config option instead if that is preferred.

Tests

Added three cases to file_history_render_spec.lua:

• a folded entry is not expanded; the cursor parks on the entry row
• an expanded entry still lands on the file row (no regression)
• single_file behaviour unchanged

make test on file_history_render_spec.lua and panel_spec.lua passes; stylua --check (2.4.1 luajit) clean; make type-check reports no new diagnostics (the 6 pre-existing deprecated warnings in path.lua/ui/panel.lua are unrelated).