docs: link every client in the clients-page chooser + correctness sweep

The "Which should I use?" table on the clients page listed most client
names as bold text, not links — only the Decky plugin and pf-webos were
clickable — so the client references appeared broken. Link each client to
its section (or dedicated page), and fix a stale Windows headless command.

Repo-wide docs correctness/staleness pass against the code:
- steam-deck: client-not-found -> flatpak-not-found (the real backend code)
- install: host cert is punktfunk-host-windows_<ver>.cer, not ..._setup.cer
- configuration: GPU_PRIORITY_CLASS default is auto; 10BIT/444 are default-on
- how-it-works/index: GameStream/Moonlight is opt-in (--gamestream)
- roadmap: clipboard sync is shipped, not planned
- install-client: MSIX/cert artifacts are arch-suffixed (_x64/_arm64)
- requirements: fix garbled 22H2/IddCx sentence
- status: Linux encode also covers AMD/Intel (VAAPI/Vulkan Video)
- automation: add the plugins.changed event
- windows-host: note the optional bundled VB-CABLE virtual mic
- sway: PUNKTFUNK_COMPOSITOR=hyprland is a wlroots-family alias
- running-as-a-service: punktfunk-probe is a source-build-only dev tool

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

docs-site/content/docs/requirements.md

@@ -33,8 +33,8 @@ Pick your distro to install, then your desktop to configure — the two are inde
 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-
-> framework needs make 22H2 the hard floor — Windows 10 is not supported). It encodes on NVIDIA
+> signed installer that registers a service and bundles a virtual-display driver whose driver
+> framework (IddCx 1.10) makes 22H2 the hard floor — Windows 10 is not supported. It encodes on NVIDIA
 > (NVENC), AMD (AMF), or Intel (QSV), with a software fallback, and is newer than the Linux host; see
 > [Windows Host](/docs/windows-host).