Fix final naming inconsistency in database examples

Co-authored-by: hotlong <50353452+hotlong@users.noreply.github.com>

Author: Copilot

.env.example

@@ -11,8 +11,8 @@ AUTH_SECRET=your-super-secret-key-change-this-in-production
 
 # Optional: Database connection URL (defaults to SQLite: objectstack.db)
 # Examples:
-# - PostgreSQL: postgres://user:password@localhost:5432/objectos
-# - MongoDB: mongodb://localhost:27017/objectos
+# - PostgreSQL: postgres://user:password@localhost:5432/objectstack
+# - MongoDB: mongodb://localhost:27017/objectstack
 # - SQLite: sqlite:objectstack.db (or omit for default)
 # OBJECTQL_DATABASE_URL=sqlite:objectstack.db