core: slide terminal keybinding action

src/Surface.zig

@@ -3856,6 +3856,12 @@ pub fn performBindingAction(self: *Surface, action: input.Binding.Action) !bool
             .toggle,
         ),
 
+        .toggle_slide_terminal => {
+            if (@hasDecl(apprt.Surface, "toggleSlideTerminal")) {
+                self.rt_surface.toggleSlideTerminal();
+            } else log.warn("runtime doesn't implement toggleSlideTerminal", .{});
+        },
+
         .select_all => {
             const sel = self.io.terminal.screen.selectAll();
             if (sel) |s| {

src/input/Binding.zig

@@ -363,6 +363,17 @@ pub const Action = union(enum) {
     /// This only works on macOS, since this is a system API on macOS.
     toggle_secure_input: void,
 
+    /// Toggle the "slide" terminal. The slide terminal is a terminal that
+    /// slides in from some screen edge, usually the top. This is useful for
+    /// quick access to a terminal without having to open a new window or tab.
+    ///
+    /// The slide terminal is a singleton; only one instance can exist at a
+    /// time.
+    ///
+    /// See the various configurations for the slide terminal in the
+    /// configuration file to customize its behavior.
+    toggle_slide_terminal: void,
+
     /// Quit ghostty.
     quit: void,
 
@@ -382,6 +393,10 @@ pub const Action = union(enum) {
     ///
     crash: CrashThread,
 
+    pub const SlideTerminalPosition = enum {
+        top,
+    };
+
     pub const CrashThread = enum {
         main,
         io,