Full screen is the page on black and nothing else: one page (or one spread,
when two-page view was on, #1353) fitted to the screen, from the current
page; a click, Space, Enter, the arrows and Page Up/Down turn pages, a
shift-click and Backspace go back; Esc brings the display from before
back at the page reached. The quick tools are not drawn in full screen.
Transitions, auto-advance, loop and the cursor hiding stay planned.
Refs #379.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RUNQSPVXx3dDBabRZHAnjz