fb23e4c7cb
During Loading state (before VHI is built), j/k used to jump by logical line, visually skipping multiple wrapped rows. Now uses v_sub_offset to track position within a wrapped line, enabling smooth 1-visual-row scroll. - Add v_sub_offset field to App for sub-line visual position tracking - scroll_down/up_line else branch: advance v_sub_offset, wrap to next line - ensure_viewport_cache Loading path: pass v_sub_offset as offset_in_line - ensure_cursor_visible: skip during Loading (scroll functions manage it) - Reset v_sub_offset on Loading→Ready, scroll_to_top, scroll_to_bottom - Add 3 tests for Loading-state sub-offset scrolling behavior