Add FullscreenZoom

[kaikimax]

Adds FullscreenZoom, a lightweight fullscreen zoom/pan tool for Windows — tray-resident, controlled entirely by one-handed hotkeys (Alt+Z/R/Q, Alt+Up/Down), no config panel or drawing/recording features, just smooth cursor-following zoom.

Distinct from the existing entries in this category:

• vs. magnify-snap: that's a panel-driven tool with fixed preset zoom levels; this is continuous zoom/pan via hotkeys, no panel.
• vs. ZoomIt: that's a full presentation toolkit (zoom + drawing + screen recording + OCR + timers); this does zoom only, with a smaller footprint for people who don't need the rest.