client-login: hard reload to /contributor instead of setSession+router.push

The previous attempt at hydrating the Supabase browser client via
supabase.auth.setSession() was racing against the server-set cookie.
The server cookie was written with Path=/; SameSite=Lax (no Secure
flag — Next.js cookies().set defaults), but the browser supabase
client's setAll handler writes cookies with Secure; SameSite=None.
The two writes for the same cookie name produced inconsistent state.

Drop setSession + router.push entirely. Instead, do a hard
window.location.href = '/contributor' redirect after a successful
POST. The server renders /contributor with the freshly-set auth
cookie; the browser supabase client boots up reading it from
document.cookie on page load. No client-side hydration race.

src/app/client-login/page.tsx

@@ -33,20 +33,14 @@ export default function ClientLoginPage() {
         return;
       }
 
-      // Hydrate Supabase client with the session from the API response so
-      // AuthContext picks it up immediately and the next render of
-      // /contributor sees an authenticated user (no flash of logged-out
-      // state, no race against cookie propagation).
-      if (data.session?.access_token && data.session?.refresh_token) {
-        await supabase.auth.setSession({
-          access_token: data.session.access_token,
-          refresh_token: data.session.refresh_token,
-        });
-      }
-
-      // Redirect to contributor dashboard (fresh session in AuthContext)
-      router.push('/contributor');
-      router.refresh();
+      // The wp-login API has already set the supabase session cookie via
+      // its NextResponse. Do a HARD reload to /contributor so the server
+      // re-renders with that cookie and the browser supabase client
+      // boots up reading it from document.cookie. Avoids the cookie-flag
+      // mismatch that happens if we try to setSession() client-side
+      // (browser client writes Secure;SameSite=None, server writes
+      // SameSite=Lax — they conflict).
+      window.location.href = '/contributor';
     } catch (err: any) {
       setError(err.message || 'An error occurred');
       console.error('Login exception:', err);