fix: restore to_n1ql to render interpolated values for copy-paste use

to_n1ql delegated to to_n1ql_with_params.first, which returns a query
with positional placeholders ($1, $2) instead of literal values. This
broke the method's main external use case: producing a query you can
copy-paste into the database. Build the query with interpolated values
(params: nil) so to_n1ql keeps its previous, human-readable output while
to_n1ql_with_params remains the parameterized path used internally.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: pimpin

lib/couchbase-orm/relation.rb

@@ -20,7 +20,11 @@ def to_s
             end
 
             def to_n1ql
-                to_n1ql_with_params.first
+                bucket_name = @model.bucket.name
+                where = build_where_with_params(nil)
+                order = build_order
+                limit = build_limit
+                "select raw meta().id from `#{bucket_name}` where #{where} order by #{order} #{limit}"
             end
 
             def to_n1ql_with_params