WIP - fix browser refresh not holding user authentication

frontend/server/api/auth/login.post.ts

@@ -56,15 +56,15 @@ export default defineEventHandler(async (event) => {
     setSessionCookie(event, access_token)
     
     // Set tenant ID cookie (readable by client for context)
-    if (tenantId) {
-      setTenantIdCookie(event, tenantId)
-    }
+    // Use tenantId from response, or fall back to subdomain
+    const tenantToStore = tenantId || subdomain
+    setTenantIdCookie(event, tenantToStore)
 
     // Return user info (but NOT the token - it's in HTTP-only cookie)
     return {
       success: true,
       user,
-      tenantId,
+      tenantId: tenantToStore,
     }
   } catch (error: any) {
     // Re-throw H3 errors