fix(auth): use absolute positioning for Turnstile container

h-0 w-0 overflow-hidden was clipping the iframe, preventing
Turnstile from executing. absolute takes it out of flow without
clipping, fixing both the layout gap and the captcha failure.

Author: waleedlatif1

apps/sim/app/(auth)/login/login-form.tsx

@@ -472,7 +472,7 @@ export default function LoginPage({
           </div>
 
           {turnstileSiteKey && (
-            <div className='h-0 w-0 overflow-hidden'>
+            <div className='absolute'>
               <Turnstile
                 ref={turnstileRef}
                 siteKey={turnstileSiteKey}

apps/sim/app/(auth)/signup/signup-form.tsx

@@ -478,7 +478,7 @@ function SignupFormContent({
           </div>
 
           {turnstileSiteKey && (
-            <div className='h-0 w-0 overflow-hidden'>
+            <div className='absolute'>
               <Turnstile
                 ref={turnstileRef}
                 siteKey={turnstileSiteKey}