fix: attach keyboard tracking view in advance and only when window has been changed (#1170)

## 📜 Description Fixed strange animation introduced by `react-native-keyboard-controller`. ## 💡 Motivation and Context This regression was introduced in #1158 Basiucally I discovered 2 issues: - the tracking view could be attached later to the window so we could see "unreal" values, where keyboard height would be equal to whole screen size and `progress` could be 2+ #1166 (comment) - since we start to attach tracking view to each new window we can attach it to system alerts etc. #1169 So the manner that we choose was slightly agressive. The original issue was caused by fact that tracking view gets detached when modal appears. But when `Alert`/transparent `Modal` are shown, then we don't need to re-attach a veiw, because old view is not detached. Additionally I didin't like the fact that we subscribe to `didBecomeVisibleNotification` event, which gets triggered every time before the keyboard appears (potentially it may slow down the app). So in this PR I decided to re-work the approach. Now instead of "try to attach to top window root view" we follow approach "re-attach tracking view only if current tracking view was detached". And this approach works better because: - we don't attach listener for each new window (attach it only when necessary) - we attach it **before** keyboard starts its movement. So new solution seems to work better and fix all the issues caused by its previous implementation. Also I think it's worth to mention several solutions that didn't work: - I tried to use KVO on `view.window` property and it didn't give a desired behavior (listener was never called); - I tried to avoid using `keyboardLayoutGuide`, but when keyboard disappear - I again don't receive animation and animate instantly to the end position 🤷‍♂️ - I tried to attach tracking view to window but in this case it's not tracking any updates and it's not visible 🤷‍♂️ Closes #1169 ## 📢 Changelog <!-- High level overview of important changes --> <!-- For example: fixed status bar manipulation; added new types declarations; --> <!-- If your changes don't affect one of platform/language below - then remove this platform/language --> ### iOS - added `isAttaching` property (`willMove` can be called when we call `removeFromSuperview`/`addSubview` inside `attachToTopmostView` and we need to filter out these operations to avoid potential bugs; - replace `didBecomeVisibleNotification` mechanism with `willMove(toWindow`; - call `attachToTopmostView` pro-actively on first mount to start window observation. ## 🤔 How Has This Been Tested? Tested in example app + repro (iPhone 16 Pro - iOS 26.0, iPhone 14 Pro - iOS 16.4) ## 📸 Screenshots (if appropriate): |Before|After|Issue| |------|-----|------| |<video src="https://github.com/user-attachments/assets/0b7ab951-5a19-400e-b540-061df2c933a9">|<video src="https://github.com/user-attachments/assets/8653bee3-78c4-4b18-a6ea-312923779bd7">|https://github.com/kirillzyusko/react-native-keyboard-controller/issues/1166#issuecomment-3419679794| |<video src="https://github.com/user-attachments/assets/a48fb605-d7e9-484a-bec1-c87d601cdd85">|<video src="https://github.com/user-attachments/assets/614b9c78-b8ae-4918-9e06-8f18e1516a8f">|https://github.com/kirillzyusko/react-native-keyboard-controller/issues/1169| ## 📝 Checklist - [x] CI successfully passed - [x] I added new mocks and corresponding unit-tests if library API was changed

Author: kirillzyusko

ios/observers/movement/KeyboardTrackingView.swift

@@ -15,6 +15,7 @@ final class KeyboardTrackingView: UIView {
  private var keyboardView: UIView? { KeyboardViewLocator.shared.resolve() }
  private var keyboardHeight = 0.0
  private weak var currentAttachedView: UIView?
+ private var isAttaching = false
 
  static let invalidPosition: CGFloat = -.greatestFiniteMagnitude
 
@@ -55,19 +56,22 @@ final class KeyboardTrackingView: UIView {
  name: UIResponder.keyboardDidShowNotification,
  object: nil
  )
- NotificationCenter.default.addObserver(
- self,
- selector: #selector(attachToTopmostView),
- name: UIWindow.didBecomeVisibleNotification,
- object: nil
- )
+ attachToTopmostView()
+ }
+
+ override func willMove(toWindow newWindow: UIWindow?) {
+ // When the view is being removed from the window, we need to re-attach it
+ if newWindow == nil, !isAttaching {
+ attachToTopmostView()
+ }
  }
 
  @objc private func attachToTopmostView() {
  guard let topView = UIApplication.topViewController()?.view else { return }
 
  if currentAttachedView === topView { return }
 
+ isAttaching = true
  removeFromSuperview()
 
  topView.addSubview(self)
@@ -87,6 +91,7 @@ final class KeyboardTrackingView: UIView {
  heightAnchor.constraint(equalToConstant: 0),
  ])
  }
+ isAttaching = false
  }
 
  @objc private func keyboardWillAppear(_ notification: Notification) {