feat(ui): add back Pause Menu, this time separate from Status panel

Assets/Scripts/UI/MainGame/PauseMenu.uxml

@@ -0,0 +1,19 @@
+<ui:UXML xmlns:ui="UnityEngine.UIElements" xsi="http://www.w3.org/2001/XMLSchema-instance"
+         engine="UnityEngine.UIElements" editor="UnityEditor.UIElements"
+         noNamespaceSchemaLocation="../../../../../UIElementsSchema/UIElements.xsd" editor-extension-mode="False">
+    <Style src="project://database/Assets/DesignSystem/Resources/UI/Styles/DesignSystem/DesignSystem.uss"/>
+    <ui:Template name="pauseOverlayTemplate" src="project://database/Assets/Scripts/UI/Common/PauseOverlay.uxml"/>
+    <ui:Template name="settingsOverlayTemplate" src="project://database/Assets/Scripts/UI/Common/SettingsOverlay.uxml"/>
+
+    <ui:VisualElement name="pause-overlay-host"
+                      style="position: absolute; left: 0; right: 0; top: 0; bottom: 0; display: none;">
+        <ui:Instance template="pauseOverlayTemplate"
+                     style="position: absolute; left: 0; right: 0; top: 0; bottom: 0;"/>
+    </ui:VisualElement>
+
+    <ui:VisualElement name="settings-overlay-host"
+                      style="position: absolute; left: 0; right: 0; top: 0; bottom: 0; display: none;">
+        <ui:Instance template="settingsOverlayTemplate"
+                     style="position: absolute; left: 0; right: 0; top: 0; bottom: 0;"/>
+    </ui:VisualElement>
+</ui:UXML>

Assets/Scripts/UI/MainGame/PauseMenuController.cs

@@ -0,0 +1,147 @@
+using System;
+using Core.Constants;
+using Events.Game;
+using Events.UI;
+using UI.Common;
+using UnityEngine;
+using UnityEngine.SceneManagement;
+using UnityEngine.UIElements;
+
+namespace UI.MainGame
+{
+    [RequireComponent(typeof(UIDocument))]
+    public class PauseMenuController : MonoBehaviour
+    {
+        [SerializeField] private UIDocument uiDocument;
+
+        [SerializeField] private PointerOverUiEventChannel pointerOverUiChannel;
+
+        [SerializeField] private PauseStateEventChannel pauseStateChannel;
+
+        private bool _isPaused;
+        private VisualElement _pauseOverlay;
+        private VisualElement _pauseOverlayHost;
+        private bool _pauseUiInitialized;
+        private bool _pointerBlockersRegistered;
+        private VisualElement _root;
+        private SettingsPanelController _settingsPanelController;
+        private UiPointerTracker _uiPointerTracker;
+
+        private void Awake()
+        {
+            if (uiDocument == null)
+                uiDocument = GetComponent<UIDocument>();
+        }
+
+        private void LateUpdate()
+        {
+            if (!Input.GetKeyDown(KeyCode.Escape))
+                return;
+
+            if (_settingsPanelController is { IsOpen: true })
+            {
+                _settingsPanelController.Hide();
+                return;
+            }
+
+            SetPaused(!_isPaused);
+        }
+
+        private void OnEnable()
+        {
+            if (uiDocument == null || uiDocument.rootVisualElement == null)
+                return;
+
+            _root = uiDocument.rootVisualElement;
+            InitializePauseUi();
+            RegisterUiPointerBlockers();
+        }
+
+        private void OnDisable()
+        {
+            SetPaused(false);
+        }
+
+        private void InitializePauseUi()
+        {
+            if (_pauseUiInitialized || _root == null)
+                return;
+
+            _pauseOverlay = _root.Q<VisualElement>(SharedUiElementNames.Pause.Overlay);
+            _pauseOverlayHost = _root.Q<VisualElement>(SharedUiElementNames.Pause.OverlayHost);
+            var title = _root.Q<Label>(SharedUiElementNames.Pause.Title);
+            var resumeButton = _root.Q<Button>(SharedUiElementNames.Pause.ResumeButton);
+            var settingsButton = _root.Q<Button>(SharedUiElementNames.Pause.SettingsButton);
+            var quitButton = _root.Q<Button>(SharedUiElementNames.Pause.QuitButton);
+
+            if (title == null || resumeButton == null || settingsButton == null || quitButton == null)
+                throw new InvalidOperationException("[PauseMenuController] Pause elements missing in PauseMenu UXML.");
+
+            title.text = "Paused";
+            if (_pauseOverlayHost != null)
+                _pauseOverlayHost.style.display = DisplayStyle.None;
+            _pauseOverlay.style.display = DisplayStyle.None;
+            resumeButton.clicked += () => { SetPaused(false); };
+            settingsButton.clicked += () => { _settingsPanelController.Toggle(); };
+            quitButton.clicked += QuitToMainMenu;
+            _settingsPanelController = new SettingsPanelController(_root, false);
+            _pauseUiInitialized = true;
+        }
+
+        private void RegisterUiPointerBlockers()
+        {
+            if (_pointerBlockersRegistered || _root == null)
+                return;
+
+            if (pointerOverUiChannel == null)
+                throw new InvalidOperationException(
+                    "[PauseMenuController] Pointer Over UI event channel is not assigned. " +
+                    "Assign the SAME PointerOverUiEventChannel asset that is set on GameProjectInstaller.");
+
+            _uiPointerTracker = new UiPointerTracker(pointerOverUiChannel);
+            TrackPointerBlocker(SharedUiElementNames.Pause.OverlayHost);
+            TrackPointerBlocker(SharedUiElementNames.Settings.OverlayHost);
+            _pointerBlockersRegistered = true;
+        }
+
+        private void TrackPointerBlocker(string elementName)
+        {
+            var element = _root.Q<VisualElement>(elementName);
+            _uiPointerTracker.Track(element);
+        }
+
+        private void SetPaused(bool paused)
+        {
+            if (_isPaused == paused)
+                return;
+
+            _isPaused = paused;
+            Time.timeScale = paused ? 0f : 1f;
+
+            if (pauseStateChannel)
+                pauseStateChannel.Raise(paused);
+
+            if (_pauseOverlayHost != null)
+                _pauseOverlayHost.style.display = paused ? DisplayStyle.Flex : DisplayStyle.None;
+            if (_pauseOverlay != null)
+                _pauseOverlay.style.display = paused ? DisplayStyle.Flex : DisplayStyle.None;
+
+            if (!paused && _settingsPanelController != null && _settingsPanelController.IsOpen)
+                _settingsPanelController.Hide();
+
+            // A full-screen overlay that hides under a stationary pointer never emits PointerLeave,
+            // so explicitly clear its pointer-over-UI state when leaving the paused state.
+            if (!paused && _uiPointerTracker != null)
+            {
+                _uiPointerTracker.Release(_pauseOverlayHost);
+                _uiPointerTracker.Release(_root?.Q<VisualElement>(SharedUiElementNames.Settings.OverlayHost));
+            }
+        }
+
+        private static void QuitToMainMenu()
+        {
+            Time.timeScale = 1f;
+            SceneManager.LoadScene(SceneNames.MainMenu);
+        }
+    }
+}