fix(stats): decode stage measures GPU completion; Alt+Enter fullscreen alias

The Vulkan path's receive_frame returns at SUBMISSION (~0.1 ms) — the
hardware decodes asynchronously, so the decode stat was truthful but
measured the wrong boundary. The pump now ships the frame to the
presenter FIRST, then waits the frame's timeline fence (vkWaitSemaphores
resolved through the shared device's proc chain) and stamps
received→decode-COMPLETE — true NVDEC time at zero pipeline cost, since
the presenter's own GPU wait is what actually gates sampling. Software/
VAAPI keep their synchronous stamps.

Also: Alt+Enter joins F11 as the fullscreen toggle (some keyboards' Fn
layer sends a media key for plain F11 — observed on glass as
'F11 only works with shift'); the shell's shortcuts panel lists both.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

docs-site/content/docs/requirements.md

@@ -26,11 +26,11 @@ is also available. Setup splits along two axes: you **install** the package per
 - [KDE Plasma (KWin)](/docs/kde)
 - [GNOME (Mutter)](/docs/gnome)
 - [Steam / gamescope](/docs/gamescope)
+- [Hyprland](/docs/hyprland)
 - [Sway / wlroots](/docs/sway)
 
-Pick your distro to install, then your desktop to configure — the two are independent. Other
-wlroots compositors (Hyprland) work but aren't a primary target; the host still needs one of these
-compositor backends to create a virtual display.
+Pick your distro to install, then your desktop to configure — the two are independent. The host
+needs one of these compositor backends to create a virtual display.
 
 > **Windows host:** punktfunk also runs as a native host on **Windows 11 22H2 or newer (x64)** — a
 > signed installer that registers a service and bundles a virtual-display driver (whose driver-