Problem

On macOS 26.5 / 26.5.1, BambuStudio either hangs for a long time on startup (#10968) or crashes within ~20 s of launch (#11004), with steadily growing memory use in both cases. The crash is an Apple-Silicon pointer-authentication failure:

Exception: EXC_BAD_ACCESS (SIGSEGV)
Subtype:   KERN_INVALID_ADDRESS ... possible pointer authentication failure

0  BambuStudio  WebView::CreateWebView(...)::$_0::operator()(wxWebView*) const + 240
1  BambuStudio  wxAsyncMethodCallEventFunctor<...>::Execute() + 156

Likely cause

WebView::CreateWebView registers the "wx" script message handler from a CallAfter() callback. The callback captures the raw webView pointer and calls AddScriptMessageHandler() on it.

The stack (a CreateWebView lambda invoked from wxAsyncMethodCallEventFunctor::Execute, failing with a PAC error on a corrupted pointer) is consistent with the WebKit view being torn down before this async callback runs, so the callback would dereference a freed wxWebView* (use-after-free). I am inferring the use-after-free from the stack and the PAC failure — I have not confirmed it with a heap / ASan trace — but the captured raw pointer makes it possible and it is the most likely explanation. On Apple Silicon a corrupted pointer trips pointer authentication → hard crash; elsewhere the same path surfaces as the long startup hang.

The same hazard applies to g_delay_webviews, which holds raw pointers that are never cleared when a view is destroyed.

Fix

• In the CallAfter lambda, check g_webviews (the list of live views) and bail out if webView has already been destroyed.
• In ~WebViewRef, also remove the view from g_delay_webviews, so a later flush of the delayed list can never touch a freed view.

Small, self-contained change: no effect on Windows (the block runs synchronously there) and no functional change on the healthy path. The guards are defensive and correct regardless of whether the use-after-free is the exact mechanism.

Fixes #11004
Fixes #10968