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/sway.md

@@ -27,7 +27,7 @@ The host auto-detects a wlroots session, so you usually need nothing here. To fo
 these in `~/.config/punktfunk/host.env`:
 
 ```ini
-PUNKTFUNK_COMPOSITOR=wlroots      # aliases: sway, wlr (Hyprland has its own: PUNKTFUNK_COMPOSITOR=hyprland)
+PUNKTFUNK_COMPOSITOR=wlroots      # aliases: sway, wlr, hyprland (all the wlroots family; the exact backend is auto-detected)
 PUNKTFUNK_INPUT_BACKEND=wlr
 PUNKTFUNK_VIDEO_SOURCE=virtual
 # GPU zero-copy capture→encode is ON by default; auto-falls back to CPU. Set PUNKTFUNK_ZEROCOPY=0 to force CPU.