fix: Show "Verifying..." loading state on login button while Turnstile loads

The Sign In button was disabled during Turnstile verification but still
displayed "Sign In", making it unclear why the button was non-interactive.

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

Author: sirjamesgray

app/components/forms/login-form.tsx

@@ -322,7 +322,12 @@ export function LoginForm() {
           className="w-full"
           disabled={isLoading || isLockedOut || !isTurnstileVerified}
         >
-          {isLoading ? 'Signing in...' : isLockedOut ? `Locked (${formatCountdown(countdown!)})` : 'Sign In'}
+          {isLoading ? 'Signing in...' : isLockedOut ? `Locked (${formatCountdown(countdown!)})` : !isTurnstileVerified ? (
+            <span className="flex items-center gap-2">
+              <Icon name="Loader" size={16} className="animate-spin" />
+              Verifying...
+            </span>
+          ) : 'Sign In'}
         </Button>
       </form>