Enable VibeChat UTUN service and package the Wintun driver

Add a settings button to open the current config in an external editor. Wait for core, UTUN and chat startup before reporting readiness; verify startup failures and restarts. Include Wintun DLL and license notices in Windows builds and installers.

src/tun_windows.c

@@ -47,7 +47,7 @@ static int wintun_load_dll(void)
     if (!wintun_dll) wintun_dll = LoadLibraryA("wintun.dll");
 
     if (!wintun_dll) {
-        DEBUG_ERROR(DEBUG_CATEGORY_TUN, "wintun.dll not found");
+        DEBUG_ERROR(DEBUG_CATEGORY_TUN, "Cannot load wintun.dll; place it beside the executable: error=%lu", GetLastError());
         return -1;
     }