fix: bug: Desktop Connect button never renders at 1280px width (#399)

Replace screen.width with window.innerWidth in useMobile composable.
screen.width reports the physical screen size (0 in headless Chromium),
while window.innerWidth reflects the actual viewport — the correct metric
for responsive layout. The previous Object.defineProperty workaround in
wallet-provider.ts could not override the native Screen.prototype getter,
so screen.width remained 0, isMobile stayed true, and ConnectButton was
never rendered. Fix wallet-provider.ts to pass viewport/screen options
directly to browser.newContext() and remove the broken init-script shim.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/setup/wallet-provider.ts

@@ -29,20 +29,9 @@ export async function createWalletContext(
   const address = wallet.address;
   const chainIdHex = `0x${chainId.toString(16)}`;
 
-  const context = await browser.newContext();
-
-  // Override screen.width to ensure desktop mode (the app uses screen.width for mobile detection)
-  // In headless CI environments, screen.width may not match the viewport
-  await context.addInitScript(() => {
-    Object.defineProperty(window.screen, 'width', {
-      configurable: true,
-      value: 1280,
-    });
-    Object.defineProperty(window.screen, 'availWidth', {
-      configurable: true,
-      value: 1280,
-    });
-    console.info('[wallet-provider] Set screen.width to 1280 for desktop mode');
+  const context = await browser.newContext({
+    viewport: { width: 1280, height: 720 },
+    screen: { width: 1280, height: 720 },
   });
 
   await context.addInitScript(() => {

web-app/src/composables/useMobile.ts

@@ -10,7 +10,7 @@ export function useMobile() {
 
   isMobile.value = isMobileFunc();
   function isMobileFunc() {
-    if (screen.width <= 768) {
+    if (window.innerWidth <= 768) {
       return true;
     } else {
       return false;