feat(sway): 4K scale 2, natural mouse scroll, idle inhibit for emulators

Three unrelated desktop-side fixes, all in home/sway.nix.

Sway cannot key an output rule on resolution, so scale 2 on 4K displays
is applied by a user service that runs once at session start and again on
every output event, which is what makes it survive a display being
switched off and on. The scale guard in the jq filter stops the
subscription feeding itself. kanshi still owns mode and position; no
profile here sets a scale, so the two do not fight.

natural_scroll on type:pointer gives mice the same scroll direction as
the touchpads already had.

PCSX2 and Dolphin default to borderless-windowed rather than compositor
fullscreen, so the existing inhibit_idle fullscreen rules never matched
and swaylock engaged mid-game. Inhibit on focus for the emulators
instead. The Steam session is unaffected either way: swayidle is wanted
by graphical-session.target and conditional on WAYLAND_DISPLAY, and the
gamescope session provides neither.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

docs/hosts/console.md

@@ -124,6 +124,25 @@ The greeter is **Dvorak**, like every other host here (`modules/sway.nix` forces
 `XKB_DEFAULT_VARIANT=dvorak` on cage). Only relevant if someone else has to type
 a password.
 
+### The Sway session behind it
+
+Two fleet-wide rules in `home/sway.nix` matter more on a television than
+anywhere else:
+
+- Any output running at 4K is forced to **scale 2** (1920x1080 logical). Sway's
+  config cannot key an output rule on resolution, so a small user service
+  applies it at session start and again on every output event — which is what
+  makes it survive the TV being switched off and on.
+- The emulators inhibit idle **while focused**, not only while fullscreen.
+  PCSX2 and Dolphin default to borderless-windowed rather than compositor
+  fullscreen, so the generic `inhibit_idle fullscreen` rules never fired and
+  swaylock cut in mid-game.
+
+Neither applies in the Steam session: `swayidle` is a home-manager user service
+wanted by `graphical-session.target` and conditional on `WAYLAND_DISPLAY`, and
+the gamescope session starts neither, so nothing locks the screen in Big
+Picture.
+
 ### Adding non-Steam titles to Big Picture
 
 RetroArch, PCSX2, Dolphin and Clone Hero are installed system-wide but are not

docs/keybindings.md

@@ -18,8 +18,8 @@ rebuild, never the generated dotfiles.
 - Letter keys are **keysyms** (the character produced), not physical positions.
   The keyboard is **Dvorak** (`us`/`dvorak`), so e.g. "Super+s" is whatever key
   types `s` in Dvorak.
-- Shortcuts apply to every Sway host (MBP, T400, Mac Pro); brightness keys are
-  laptop-only, as noted.
+- Shortcuts apply to every Sway host (MBP, T400, Mac Pro, Console); brightness
+  keys are laptop-only, as noted.
 
 ---