Fix browser freeze after pane split by reattaching WKWebView rendering state (manaflow-ai#1852)

When a pane split occurs, SwiftUI recreates host views and the portal
system rebinds the WKWebView to a new container. However, the bind path
never called BrowserWindowPortalRegistry.refresh(), so WebKit's internal
rendering state (_exitInWindow/_enterInWindow) was never cycled. This
left the WKWebView frozen in the original pane after a split.

Add refresh() calls after every portal bind that changes the host, in
three code paths: the main update path (shouldBindNow), onDidMoveToWindow,
and onGeometryChanged. The refresh is a no-op when no reattach is needed
(browserPortalNeedsRenderingStateReattach == false), so normal rendering
is unaffected.

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: Apptah

Sources/Panels/BrowserPanelView.swift

@@ -6098,6 +6098,10 @@ struct WebViewRepresentable: NSViewRepresentable {
                 visibleInUI: coordinator.desiredPortalVisibleInUI,
                 zPriority: coordinator.desiredPortalZPriority
             )
+            BrowserWindowPortalRegistry.refresh(
+                webView: webView,
+                reason: "portalHostBind.didMoveToWindow"
+            )
             BrowserWindowPortalRegistry.updatePaneTopChromeHeight(
                 for: webView,
                 height: coordinator.desiredPortalVisibleInUI ? paneTopChromeHeight : 0
@@ -6129,6 +6133,10 @@ struct WebViewRepresentable: NSViewRepresentable {
                     visibleInUI: coordinator.desiredPortalVisibleInUI,
                     zPriority: coordinator.desiredPortalZPriority
                 )
+                BrowserWindowPortalRegistry.refresh(
+                    webView: webView,
+                    reason: "portalHostBind.geometryChanged"
+                )
                 BrowserWindowPortalRegistry.updatePaneTopChromeHeight(
                     for: webView,
                     height: coordinator.desiredPortalVisibleInUI ? paneTopChromeHeight : 0
@@ -6166,6 +6174,14 @@ struct WebViewRepresentable: NSViewRepresentable {
                     visibleInUI: coordinator.desiredPortalVisibleInUI,
                     zPriority: coordinator.desiredPortalZPriority
                 )
+                // Force a rendering-state reattach after portal host replacement
+                // (e.g. after a pane split). Without this, WKWebView can freeze
+                // because _exitInWindow/_enterInWindow are never cycled when the
+                // web view is reparented to a new container during bind.
+                BrowserWindowPortalRegistry.refresh(
+                    webView: webView,
+                    reason: "portalHostBind"
+                )
                 coordinator.lastPortalHostId = hostId
                 coordinator.lastSynchronizedHostGeometryRevision = geometryRevision
             }