fix: dashboard 'Add Existing Account' dialog buried on phones/tablets

On device-phone/device-tablet, style.css pins every .window to
z-index 9999999 !important — including the fullpage dashboard window.
The Add Existing Account login dialog opens with backdrop: true, and
the .window-backdrop wrapper is not a .window, so it kept its small
inline z-index and rendered entirely behind the dashboard.

Pass stay_on_top: true like every other backdropped dashboard dialog,
and make the Forgot-password child dialog inherit the flag so it does
not open buried under the now stay-on-top login window's backdrop.

Verified with Playwright on iPhone 13 emulation and a desktop
viewport: login and recover-password dialogs stack above the
dashboard in both.

src/gui/src/UI/Dashboard/UIDashboard.js

@@ -746,6 +746,12 @@ async function UIDashboard (options) {
                             backdrop: true,
                             close_on_backdrop_click: true,
                             parent_center: true,
+                            // Phones/tablets pin every .window to one z-index
+                            // (style.css), which puts the fullpage dashboard
+                            // above this dialog's backdrop wrapper; stay_on_top
+                            // lifts the dialog into the 99999999+ band like
+                            // every other backdropped dashboard dialog.
+                            stay_on_top: true,
                         },
                     });
                 },

src/gui/src/UI/UIWindowLogin.js

@@ -389,7 +389,10 @@ async function UIWindowLogin (options) {
             UIWindowRecoverPassword({
                 window_options: {
                     backdrop: true,
-                    stay_on_top: isMobile.phone,
+                    // A stay-on-top login window (dashboard mode) sits in the
+                    // 99999999+ band; this dialog must join it there or it
+                    // opens buried under the login window's backdrop.
+                    stay_on_top: isMobile.phone || !!options.window_options?.stay_on_top,
                     close_on_backdrop_click: false,
                 },
             });