fix(webapp): log Google auth conflict as warn instead of error

Author: d-cs

.server-changes/google-auth-conflict-warn.md

@@ -0,0 +1,6 @@
+---
+area: webapp
+type: improvement
+---
+
+Downgrade the "Google auth conflict" log from `error` to `warn`. This branch handles an expected user-state mismatch (Google ID belongs to one user, email is on another) by returning the existing auth user — there's no exception to chase, so it shouldn't page on the Sentry error channel.

apps/webapp/app/models/user.server.ts

@@ -233,7 +233,7 @@ export async function findOrCreateGoogleUser({
     // Check if email user and auth user are the same
     if (existingEmailUser.id !== existingUser.id) {
       // Different users: email is taken by one user, Google auth belongs to another
-      logger.error(
+      logger.warn(
         `Google auth conflict: Google ID ${authenticationProfile.id} belongs to user ${existingUser.id} but email ${email} is taken by user ${existingEmailUser.id}`,
         {
           email,