input: "ignore" binding action are still be processed by the OS/GUI (#7474)

Related to #7468

This changes the behavior of "ignore". Previously, Ghostty would
consider "ignore" actions consumed but do nothing. They were like a
black hole. Now, Ghostty returns `ignored` which lets the apprt forward
the event to the OS/GUI.

This enables keys that would otherwise be pty-encoded to be processed
later, such as for GTK to show the GTK inspector.

src/Surface.zig

@@ -2069,14 +2069,20 @@ fn maybeHandleBinding(
         break :performed try self.performBindingAction(action);
     };
 
+    if (performed) {
         // If we performed an action and it was a closing action,
         // our "self" pointer is not safe to use anymore so we need to
         // just exit immediately.
-    if (performed and closingAction(action)) {
+        if (closingAction(action)) {
             log.debug("key binding is a closing binding, halting key event processing", .{});
             return .closed;
         }
 
+        // If our action was "ignore" then we return the special input
+        // effect of "ignored".
+        if (action == .ignore) return .ignored;
+    }
+
     // If we have the performable flag and the action was not performed,
     // then we act as though a binding didn't exist.
     if (leaf.flags.performable and !performed) {

src/input/Binding.zig

@@ -222,13 +222,20 @@ pub fn lessThan(_: void, lhs: Binding, rhs: Binding) bool {
 
 /// The set of actions that a keybinding can take.
 pub const Action = union(enum) {
-    /// Ignore this key combination, don't send it to the child process, just
-    /// black hole it.
+    /// Ignore this key combination, don't send it to the child process,
+    /// pretend that it never happened at the Ghostty level. The key
+    /// combination may still be processed by the OS or other
+    /// applications.
     ignore,
 
     /// This action is used to flag that the binding should be removed from
     /// the set. This should never exist in an active set and `set.put` has an
     /// assertion to verify this.
+    ///
+    /// This is only able to unbind bindings that were previously
+    /// bound to Ghostty. This cannot unbind bindings that were not
+    /// bound by Ghostty (e.g. bindings set by the OS or some other
+    /// application).
     unbind,
 
     /// Send a CSI sequence. The value should be the CSI sequence without the