New ox_page_view.py with OxPageViewPanel: canvas rendering at device
resolution (800x480 Orion, 320x240 Rion), RGB565 color conversion,
widget tree, selection handles, drag-move, device frame image support.
Wired into main.py with context menu, history, panel lifecycle.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
