Add frame-controls: move window controls between bar and ⋯ menu by long press

steamFrame.dashboard.frameControls: a long press (longPressMs, default
1.5 s; a ring shows the progress from half of it) on a control under a
dashboard window or on a More Options (three-dot) menu row opens a popup
with "Show in bar", which moves that control between the window's bottom
bar and the menu, for all windows. Placement is keyed by the control's
action icon, kept in the page and its localStorage (survives SteamVR
restarts); inBar / inMenu set defaults. floatInTheater gives theater
windows the Float control back.

The popup is a scene-graph panel of its own, attached to the pressed
button's (or the menu's) anchor like SteamVR's tooltips and menu, so the
bar and menu panels don't change; the menu's focus auto-close is held back
while its popup is open. Coordinates with window-curvature through its
sfui-curv-* contract. Lookups by signature ("frame-controls" in
lib/signatures.json, check-only anchors for the rest).

modules/frame-controls.nix

@@ -0,0 +1,89 @@
+# Window control bar (steamFrame.dashboard.frameControls): move the control
+# icons under SteamVR dashboard windows between the bottom bar and the More
+# Options (three-dot) menu with a long press on the icon or menu row (a popup
+# with "Show in bar"). Placement is per control type, for all windows, kept
+# across SteamVR restarts; inBar / inMenu set defaults. Optionally gives
+# theater windows the "Float" control back. Runtime patch of SteamVR's
+# dashboard page (vrwebhelper "systemui", DevTools 127.0.0.1:8087; see
+# frame-controls/patch.js for how it works), registered with
+# steam-ui-patches.nix only when enabled; it turns on the SteamVR web helper
+# debugger (steamvr-debugger.nix), which needs one SteamVR restart the first
+# time. Depends on SteamVR UI internals, found by signature
+# (lib/signatures.json, "frame-controls"; scripts/check-signatures.mjs checks
+# them offline).
+{ config, lib, pkgs, ... }:
+let
+  cfg = config.steamFrame.dashboard.frameControls;
+  inherit (lib) mkOption types;
+  inherit (import ./lib { inherit pkgs; }) mkPatch;
+
+  # Control names -> SteamVR action icon enums (the patch keys controls by icon).
+  names = [ "keyboard" "float" "dashboard" "theater" "dockLeft" "dockRight" "close" "curvature" ];
+  controlType = types.either (types.enum names) (types.strMatching "icon:[0-9]+");
+  controlList = description: mkOption {
+    type = types.listOf controlType;
+    default = [ ];
+    example = [ "curvature" ];
+    inherit description;
+  };
+in {
+  imports = [ ./steam-ui-patches.nix ./steamvr-debugger.nix ];
+
+  options.steamFrame.dashboard.frameControls = {
+    enable = lib.mkEnableOption ''
+      moving the control icons under SteamVR dashboard windows between the
+      window's bottom bar and its More Options (three-dot) menu: a long press
+      on a bar icon or a menu row opens a popup with "Show in bar"; the choice
+      applies to that control in all windows and is kept across SteamVR
+      restarts. Short presses work as usual. Runtime patch of the SteamVR
+      dashboard (steamFrame.uiPatches), applied immediately; turning it off
+      restores the stock controls (next switch)'';
+    longPressMs = mkOption {
+      type = types.ints.between 300 10000;
+      default = 1500;
+      description = ''
+        Hold time (ms) of the long press that opens the popup. A ring around
+        the icon shows the progress from half the time (at most after 1 s),
+        so ordinary clicks show nothing.
+      '';
+    };
+    inBar = controlList ''
+      Controls that start in the bar (by default: SteamVR's placement).
+      Names: ${lib.concatStringsSep ", " names}, or "icon:<n>" (the action's
+      icon number, see window.__sfuiFrameControls.dump() in the dashboard's
+      DevTools). A choice made in the popup wins until the control's entry
+      here changes.
+    '';
+    inMenu = controlList ''
+      Controls that start in the three-dot menu (same names as inBar).
+    '';
+    floatInTheater = mkOption {
+      type = types.bool;
+      default = false;
+      description = ''
+        Give windows in the theater the "Float" control (SteamVR only shows it
+        for windows docked in the dashboard): floats the window in the world,
+        like the stock button. Follows Float's placement.
+      '';
+    };
+  };
+
+  config = lib.mkIf cfg.enable {
+    assertions = [ {
+      assertion = lib.intersectLists cfg.inBar cfg.inMenu == [ ];
+      message = "steamFrame.dashboard.frameControls: ${builtins.toJSON (lib.intersectLists cfg.inBar cfg.inMenu)} in both inBar and inMenu.";
+    } ];
+
+    steamFrame.uiPatches.patches = [ {
+      name = "frame-controls";
+      endpoint = "http://127.0.0.1:8087";
+      target.title = "systemui";
+      patch = mkPatch {
+        name = "frame-controls";
+        src = ./frame-controls/patch.js;
+        opts = removeAttrs cfg [ "enable" ];
+      };
+      unpatch = ./frame-controls/unpatch.js;
+    } ];
+  };
+}