Add named layouts and a head pin for screens

Named layouts: Save current arrangement in Frametop Display Settings now
asks for a name, and saved layouts are listed with the presets under
Arrangement, with rename and delete next to the list. A named layout is
the custom arrangement under a name: each screen's place relative to
your head, width, curve, and pin, but not resolution or scale. Using one
copies it into the custom arrangement, so desktop start, Meta+Shift+R,
and Arrange now apply it unchanged; "active" remembers the name, and a
plain capture clears it. ft-layout gains save, use, layouts, rename, and
delete. A layout saved with fewer screens than there are now leaves the
others where they were saved last, or where the preset puts them.

Head pin: ft-screens' pin command takes "head" as well as left and
right, and pins the screen to the headset (device 0) where it is, like a
HUD. A head-pinned screen skips the wrist facing rule and shows whenever
the screens do. Carrying it re-pins it to the head on release, like a
wrist pin, so it can be adjusted in VR. The Visibility tab (now
Visibility & pins) sets each screen's pin: in the room, either wrist, or
your head, and the pin command now rejects anything but left, right, or
head (it used to take anything else as left). This removes the "no HUD"
limit from the docs.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

README.md

@@ -49,9 +49,11 @@ If you work in the desktop for long stretches, stop Steam from putting the heads
 | Click the curve button (next to the bar) | Curves the screen around you, or flattens it |
 | Drag the roll button sideways, or scroll on it | Rolls the screen; it snaps level near straight |
 | While carrying a screen, sweep its laser across your other controller's ring, then let go | Pins it to that wrist, at its size and distance, as you hold it when you let go; it shows while you see its front. Grab its bar to adjust it (it stays pinned); sweep across the ring again to take it off |
+| Set a screen to On your head (Frametop Display Settings, Visibility & pins) | Pins it to your head where it is, like a HUD. Grab its bar to move it; it stays on your head |
+| Save current arrangement… (Frametop Display Settings, Layout) | Saves where the screens are, with their sizes and pins, under a name. Pick a saved layout under Arrangement and press Arrange now to switch to it |
 | Meta+Shift+R in the desktop | Puts the screens back in their layout (also in the menu as Reset Screen Layout, and mappable to a mouse button) |
-| Meta+Shift+H in the desktop | Hides or shows all screens (also in the menu as Hide/Show Screens, and mappable). The Visibility & wrist tab of Frametop Display Settings can instead show them only with the dashboard open, or while you look at your wrist |
-| Play a VR game | The screens hide and your controllers stay in the game. Open the SteamVR dashboard, or press Meta+Shift+H, to see and use them. To keep them visible over games, change During VR games on the Visibility & wrist tab; the controllers still stay in the game, and you use the screens with the mouse or the dashboard |
+| Meta+Shift+H in the desktop | Hides or shows all screens (also in the menu as Hide/Show Screens, and mappable). The Visibility & pins tab of Frametop Display Settings can instead show them only with the dashboard open, or while you look at your wrist |
+| Play a VR game | The screens hide and your controllers stay in the game. Open the SteamVR dashboard, or press Meta+Shift+H, to see and use them. To keep them visible over games, change During VR games on the Visibility & pins tab; the controllers still stay in the game, and you use the screens with the mouse or the dashboard |
 
 You can map the mouse's extra buttons to actions such as Toggle SteamVR dashboard, Recenter pointer, or Head follow on/off on the Buttons page of Frametop Input Settings, and the Frame controllers' buttons on its Controllers page. Pointer speed, dot size, and the rest are on its Pointer page and take effect immediately. Head follow, which is experimental and off by default, makes the pointer come along when you turn your head: it stays put until your head turns past the leash angle, then glides back to its place in your view, and a leash of 0 keeps it fixed in your view. It's only lightly tested and not polished; tuning its settings, or improving how it feels, is open to anyone who wants to take it further.
 
@@ -64,7 +66,7 @@ This is an early release, tested on one Steam Frame (SteamOS 0.3.0 build 2026092
 - A SteamOS or SteamVR update can break parts of it until Frametop catches up. If something stops working after an update, please report it.
 - The first install downloads 1–2 GB for the build container and compiles everything on the headset, which takes several minutes.
 - During a VR game you can't show the screens with a controller button, because the game owns the buttons. Open the SteamVR dashboard, press Meta+Shift+H, or use a mapped mouse button instead.
-- Flatscreen games aren't detected as games. If your controllers end up working the screens instead of the game, set Controllers on the screens to "Only with the SteamVR dashboard open" (Frametop Display Settings, Visibility & wrist tab).
+- Flatscreen games aren't detected as games. If your controllers end up working the screens instead of the game, set Controllers on the screens to "Only with the SteamVR dashboard open" (Frametop Display Settings, Visibility & pins tab).
 - Typing follows your last click. A controller click on a panel other than the screens (the dashboard, a Steam app) doesn't move typing there; click it with the mouse, or click a screen to bring typing back.
 - The screens don't draw a mouse cursor of their own. The 3D mouse's dot or SteamVR's laser shows where you're pointing.
 - On SteamVR's Settings page, the 3D mouse shows a laser beam and a larger hit dot, like a controller. SteamVR doesn't tell other programs where that page is (unlike Steam's pages, such as Library), so the mouse used to miss most of it: clicks went through to a desktop screen behind, and the dot disappeared. As a workaround, on that page only, the laser starts near your eye and SteamVR finds the page itself. See docs/design.md.