Fix keyboard toggle flicker on iOS

Replace resignFirstResponder/becomeFirstResponder cycle with
reloadInputViews() wrapped in performWithoutAnimation when
switching between the standard keyboard and the custom
KeyboardView. This avoids the keyboard dismiss/show animation
that causes multiple layout passes and terminal flickering.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: alvarolb

Sources/SwiftTerm/iOS/iOSAccessoryView.swift

@@ -149,9 +149,7 @@ public class TerminalAccessory: UIInputView, UIInputViewAudioFeedback {
 
     @objc func toggleInputKeyboard (_ sender: UIButton) {
         guard let tv = terminalView else { return }
-        let wasResponder = tv.isFirstResponder
-        if wasResponder { _ = tv.resignFirstResponder() }
-        
+
         if tv.inputView == nil {
             #if os(visionOS)
             tv.inputView = KeyboardView (frame: CGRect (origin: CGPoint.zero,
@@ -167,8 +165,9 @@ public class TerminalAccessory: UIInputView, UIInputViewAudioFeedback {
         } else {
             tv.inputView = nil
         }
-        if wasResponder { _ = tv.becomeFirstResponder() }
-
+        UIView.performWithoutAnimation {
+            tv.reloadInputViews()
+        }
     }
 
     @objc func toggleTouch (_ sender: UIButton) {