[eric] crash: quiesce+detach outgoing webviews before dashboard-switch resetLayout (it unmounted every app/browser webview in one frame w/ CDP attached = GPU/browser SIGSEGV, the 'navigate away kills the app' self-quit)

frontend/src/shared/browserRegistry.ts

@@ -116,6 +116,10 @@ export function getWebview(browserId: string, tabId?: string): BrowserWebview |
   return registry.get(makeKey(browserId, resolvedTabId));
 }
 
+export function getAllBrowserIds(): string[] {
+  return [...new Set([...registry.keys()].map((k) => k.split(':')[0]))];
+}
+
 export function getBrowserWebviews(browserId: string): BrowserWebview[] {
   const out: BrowserWebview[] = [];
   for (const [key, wv] of registry.entries()) {

frontend/src/shared/dashboardSwitchTeardown.ts

@@ -0,0 +1,23 @@
+import { getAllViewOutputIds } from '@/shared/viewWebviewRegistry';
+import { getAllBrowserIds } from '@/shared/browserRegistry';
+import { quiesceViewWebview } from '@/shared/viewTeardown';
+import { detachBrowserCdp } from '@/shared/browserTeardown';
+
+// Switching dashboards clears every card from the store in ONE reducer (resetLayout), so React
+// unmounts all the outgoing app + browser <webview>s in a single frame. Ripping several live GPU
+// surfaces out at once (app previews) or unmounting a browser with its CDP debugger still attached
+// piles up "non-existent mailbox" errors and SIGSEGVs the GPU/browser process, taking the whole app
+// down with no crash dump (the "navigate away and it quits itself" bug). Quiesce + detach the
+// outgoing webviews ONE AT A TIME first, so only trivial surfaces are left to tear down. Bounded per
+// item (the helpers self-cap), fail-open, and keep-alive browsers are skipped so they survive the
+// switch with their session intact.
+export async function prepareDashboardSwitch(keepBrowserIds: string[]): Promise<void> {
+  const keep = new Set(keepBrowserIds);
+  for (const outputId of getAllViewOutputIds()) {
+    await quiesceViewWebview(outputId);
+  }
+  for (const browserId of getAllBrowserIds()) {
+    if (keep.has(browserId)) continue;
+    await detachBrowserCdp(browserId);
+  }
+}

frontend/src/shared/viewWebviewRegistry.ts

@@ -11,6 +11,10 @@ export function registerViewWebview(outputId: string, wv: ViewWebview): void {
   registry.set(outputId, wv);
 }
 
+export function getAllViewOutputIds(): string[] {
+  return [...registry.keys()];
+}
+
 export function unregisterViewWebview(outputId: string): void {
   registry.delete(outputId);
 }