refactor: inline _fullscreen_page_size() into space/b lambdas

The `page` local in `_handle_fullscreen_key` was computed
unconditionally in the non-exit branch but only consumed by the
space/b action lambdas (page-down / page-up).  Inlining
`self._fullscreen_page_size()` into those two lambdas means it's
only evaluated when space or b is actually pressed — j/k/g/G/[/]
now skip the call entirely.  Behavior is identical: the dict is
built and a single action is invoked per keypress, and the page
value is read at action-invocation time under the same lock.

Same Phase 4 shape as 134078d / ef176bf / b19625e — narrow the
scope of a local that was only live on one branch.

Co-authored-by: Ralphify <noreply@ralphify.co>

Author: 2 people

src/ralphify/_console_emitter.py

@@ -1441,12 +1441,11 @@ def _handle_fullscreen_key(self, key: str) -> None:
             if view is None:
                 return  # raced with exit
             if key not in ("q", FULLSCREEN_PEEK_KEY):
-                page = self._fullscreen_page_size()
                 actions: dict[str, Callable[[], object]] = {
                     "j": lambda: view.scroll_down(1),
                     "k": lambda: view.scroll_up(1),
-                    " ": lambda: view.scroll_down(page),
-                    "b": lambda: view.scroll_up(page),
+                    " ": lambda: view.scroll_down(self._fullscreen_page_size()),
+                    "b": lambda: view.scroll_up(self._fullscreen_page_size()),
                     "g": view.scroll_to_top,
                     "G": view.scroll_to_bottom,
                     PREV_ITERATION_KEY: view.prev_iteration,