fix(browser): normalize resident webview reuse

Resident nodes restored from the parking host could carry stale offscreen styles after hot reload, so reapply the permanent parking path before returning them.

packages/app/src/components/browser-webview-resident.browser.test.ts

@@ -101,6 +101,39 @@ describe("resident browser webviews", () => {
     expectResidentWebviewParking(webview as HTMLElement);
   });
 
+  it("normalizes an existing resident webview and its stale host before reusing them", () => {
+    const staleHost = document.createElement("div");
+    staleHost.id = RESIDENT_HOST_ID;
+    staleHost.style.left = "-20000px";
+    staleHost.style.width = "1280px";
+    staleHost.style.height = "800px";
+    staleHost.style.opacity = "0";
+    staleHost.style.display = "none";
+
+    const staleWebview = document.createElement("webview");
+    prepareBrowserWebview(staleWebview, {
+      browserId: "browser-stale-child",
+      initialUrl: "https://example.com",
+    });
+    staleWebview.style.display = "none";
+    staleWebview.style.width = "1px";
+    staleWebview.style.height = "1px";
+    staleWebview.style.position = "fixed";
+    staleWebview.style.left = "-20000px";
+    staleHost.appendChild(staleWebview);
+    document.body.appendChild(staleHost);
+
+    const webview = ensureResidentBrowserWebview({
+      browserId: "browser-stale-child",
+      url: "https://example.com/agent",
+    });
+
+    expect(webview).toBe(staleWebview);
+    expect(Array.from(staleHost.children)).toEqual([staleWebview]);
+    expectPermanentHostParking(staleHost);
+    expectResidentWebviewParking(staleWebview);
+  });
+
   it("parks resident webviews as an overlapping stack", () => {
     const firstWebview = ensureResidentBrowserWebview({
       browserId: "browser-first",

packages/app/src/components/browser-webview-resident.ts

@@ -117,13 +117,14 @@ export function ensureResidentBrowserWebview(input: {
 
   const resident = residentWebviewsByBrowserId.get(browserId) ?? null;
   if (resident?.isConnected) {
+    releaseResidentBrowserWebview(browserId, resident);
     return resident;
   }
 
   const existing = findBrowserWebview(browserId, ownerDocument);
   if (existing) {
     if (existing.parentElement?.id === RESIDENT_BROWSER_HOST_ID) {
-      residentWebviewsByBrowserId.set(browserId, existing);
+      releaseResidentBrowserWebview(browserId, existing);
     }
     return existing;
   }