fix(windows): use CoWaitForMultipleHandles for ARM64 WebView2 deadlock

.changes/fix-arm64-cowait.md

@@ -0,0 +1,17 @@
+---
+"wry": patch
+---
+
+Fix ARM64 WebView2 deadlock by replacing nested message pump with CoWaitForMultipleHandles.
+
+On Windows ARM64 (e.g. Snapdragon X Elite), creating a second WebView2 controller from the
+main STA thread would deadlock in MsgWaitForMultipleObjectsEx because the nested
+GetMessage/PeekMessage loop prevented COM from re-entering the apartment to deliver the
+async completion callback.
+
+This patch replaces the mpsc::channel + wait_with_pump pattern in create_environment(),
+create_controller(), and cookies_inner() with CoWaitForMultipleHandles using
+COWAIT_DISPATCH_CALLS | COWAIT_DISPATCH_WINDOW_MESSAGES, which is the COM-sanctioned
+mechanism for yielding an STA thread while preserving re-entrancy.
+
+Ref: https://github.com/npiesco/wry-arm64-deadlock (minimal reproduction)

Cargo.toml

@@ -85,6 +85,8 @@ features = [
   "Win32_System_Ole",
   "Win32_System_SystemInformation",
   "Win32_System_SystemServices",
+  "Win32_System_Threading",
+  "Win32_Security",
   "Win32_UI_Shell",
   "Win32_UI_WindowsAndMessaging",
   "Win32_Globalization",