Toggle session panel with Escape as in-game pause overlay

- Panel shows in Main while disconnected, auto-hides once a connection is
  established, and toggles open/closed with Escape in the Lobby or on a Map.
- Escape now pauses gameplay (active mode exits, cursor freed, paint and
  movement disabled) instead of ending the match directly; closing restores
  the prior mode via SwitchTo.
- Disconnect button is context-aware: leaves the session in the Lobby, acts
  as "Back to Lobby" (EndMatch) for the match authority on a Map, and stays a
  plain disconnect for non-authority clients on a Map.
- Removed the Escape->EndMatch handler from MatchManager; match end now routes
  through RequestEndMatch with the same authority routing.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Assets/Scripts/GameModeManager.cs

@@ -63,6 +63,11 @@ public class GameModeManager : MonoBehaviour
 
     private readonly List<GameMode> _modes = new List<GameMode>();
     private int _activeIndex = -1;
+    private bool _paused;
+    private int _resumeIndex = -1;
+
+    /// <summary>True while local gameplay is suspended for a modal overlay (see <see cref="SetPaused"/>).</summary>
+    public bool IsPaused => _paused;
 
     /// <summary>The currently active mode (null before startup).</summary>
     public GameMode ActiveMode =>
@@ -145,6 +150,9 @@ public class GameModeManager : MonoBehaviour
     /// </summary>
     public void BindSpectator()
     {
+        _paused = false;
+        _resumeIndex = -1;
+
         player = null;
         painter = null;
         PainterChanged?.Invoke(null);
@@ -165,6 +173,10 @@ public class GameModeManager : MonoBehaviour
     {
         if (!localPlayer) return;
 
+        // A fresh bind is a definitive state reset - drop any modal pause so the new avatar starts live.
+        _paused = false;
+        _resumeIndex = -1;
+
         var setup = localPlayer.GetComponent<NetworkPlayerSetup>();
 
         player = localPlayer;
@@ -216,6 +228,9 @@ public class GameModeManager : MonoBehaviour
     /// </summary>
     public void ReleaseToNoPlayer()
     {
+        _paused = false;
+        _resumeIndex = -1;
+
         ActiveMode?.Exit();
         _activeIndex = -1;
         _modes.Clear();
@@ -236,8 +251,54 @@ public class GameModeManager : MonoBehaviour
         Cursor.visible = true;
     }
 
+    /// <summary>
+    /// Pauses or resumes local gameplay for a full-screen modal overlay (the online session panel, opened
+    /// with Esc in the lobby/map). Pausing frees the OS cursor and suppresses ALL local input - movement,
+    /// painting, camera look and the mode-switch key - WITHOUT tearing down the mode cycle, so resuming
+    /// re-enters the exact mode that was active and restores its camera/cursor state. It mirrors the
+    /// <see cref="ReleaseToNoPlayer"/> cursor handling (Exit the active mode, then park the orbit rig in
+    /// Disabled so it stops re-grabbing the cursor every frame) but is reversible. No-op if unchanged.
+    /// </summary>
+    public void SetPaused(bool paused)
+    {
+        if (paused == _paused) return;
+        _paused = paused;
+
+        if (paused)
+        {
+            _resumeIndex = _activeIndex;
+            ActiveMode?.Exit();          // undo any FreeCam/First-Person takeover (also releases the cursor)
+            _activeIndex = -1;
+
+            // Painting and movement run off their own flags/Update loops and the orbit rig re-asserts the
+            // cursor each frame from its LookMode, so stop them all explicitly, then free the cursor. A
+            // Disabled look-mode keeps the cursor free every frame (the same trick ReleaseToNoPlayer uses).
+            if (player) player.ControlEnabled = false;
+            if (painter) painter.PaintingEnabled = false;
+            if (cameraInput)
+            {
+                cameraInput.enabled = true;
+                cameraInput.LookMode = ThirdPersonOrbitInput.OrbitLookMode.Disabled;
+            }
+            Cursor.lockState = CursorLockMode.None;
+            Cursor.visible = true;
+
+            ModeChanged?.Invoke(null);   // hide mode-following UI (the paint HUD) beneath the overlay
+        }
+        else
+        {
+            int resume = _resumeIndex;
+            _resumeIndex = -1;
+            if (resume >= 0 && resume < _modes.Count)
+                SwitchTo(resume);        // re-Enter restores player/painter/look + cursor (+ re-shows the HUD)
+            else
+                ModeChanged?.Invoke(ActiveMode);
+        }
+    }
+
     private void Update()
     {
+        if (_paused) return;
         if (_modes.Count == 0) return;
 
         if (WasSwitchPressed())