Use white PostHog logo on sign-in button and tidy auth copy

packages/ui/src/features/auth/OAuthControls.tsx

@@ -1,6 +1,6 @@
 import type { CloudRegion } from "@posthog/shared";
+import Logo from "@posthog/ui/primitives/Logo";
 import { Callout, Flex, Spinner } from "@radix-ui/themes";
-import posthogIcon from "./assets/posthog-icon.svg";
 import { RegionSelect } from "./RegionSelect";
 import { useOAuthFlow } from "./useOAuthFlow";
 
@@ -70,9 +70,9 @@ export function OAuthControls({
         {isPending ? (
           <Spinner size="1" />
         ) : (
-          <img src={posthogIcon} alt="" className="h-[20px] w-[20px]" />
+          <Logo wordmark={false} mono className="h-[20px] w-auto" />
         )}
-        {isPending ? "Cancel" : "Sign in / sign up with PostHog"}
+        {isPending ? "Cancel" : "Authenticate with PostHog"}
       </button>
     </Flex>
   );

packages/ui/src/features/auth/RegionSelect.tsx

@@ -24,7 +24,7 @@ export function RegionSelect({
           PostHog region
         </Text>
         <Text className="text-(--gray-11) text-xs">
-          Pick where your data lives
+          Select your data region
         </Text>
       </Flex>
       <div className="grid w-full grid-cols-2 gap-2">

packages/ui/src/features/auth/SignInCard.tsx

@@ -22,7 +22,7 @@ export function SignInCard({
     <Flex direction="column" gap="4">
       <Flex direction="column" gap="2">
         <Text className="font-bold text-(--gray-12) text-2xl">
-          Sign in / sign up with PostHog
+          Authenticate with PostHog
         </Text>
         <Text className="text-(--gray-11) text-sm">{subtitle}</Text>
       </Flex>