fix autofill: stop filling when no visible password field on page

Prevents autofill from filling app text inputs (e.g. R7 font selector)
after login. Now tryFill() bails out immediately if no input[type=password]
is visible — meaning we are no longer on a login form.

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

universal-runtime/manager.py

@@ -95,7 +95,7 @@ _AUTOFILL_CONTENT_JS = r"""
     for (const el of list) {
       if (isVisible(el)) return el;
     }
-    return list[0] || null;
+    return null;
   }
 
   function setNativeValue(el, v) {
@@ -115,6 +115,8 @@ _AUTOFILL_CONTENT_JS = r"""
 
   function tryFill() {
     const p = findPassField();
+    // No visible password field = not a login form; stop to avoid filling app inputs
+    if (!p) return;
     const u = findUserField(p);
     // Fill login FIRST so password-triggered re-render doesn't clear it
     if (CREDS.login && u) {