Refactor the Inspect pane's PageDown/PageUp handlers to consume the
PAGE_STEP constant from pager.rs instead of hard-coding 10. Adds
regression tests to pin the scroll delta (=10), ensuring future
viewport-aware refactors surface here rather than silently in
user-visible behaviour.
Test coverage: added page_down_scrolls_by_ten_in_inspect and
page_up_rewinds_by_ten_saturating_in_inspect (+ existing
page_keys_scroll_by_ten still passes).
Remove #[allow(dead_code)] from pager.rs now that PAGE_STEP is
consumed.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
altair823
94541523e7