Expect inner join on event-filtered reads from several streams

The joins(:event) calls in the multi-stream read scope survived
mutation testing on CI - with includes(:event) already in place their
removal degrades the query to an eager-loaded outer join instead of
breaking it. Pin the inner join in a query-shape spec, mirroring the
existing single-stream expectation.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: pjurewicz

ruby_event_store-active_record/spec/event_repository_spec.rb

@@ -294,6 +294,21 @@ module ActiveRecord
         }.to match_query_count(1)
       end
 
+      specify "inner join events when event filtering criteria present in several streams read" do
+        scope = specification.streams("stream", "other")
+        [
+          scope.of_type("type"),
+          scope.as_of,
+          scope.as_at,
+          scope.older_than(Time.now),
+          scope.older_than_or_equal(Time.now),
+          scope.newer_than(Time.now),
+          scope.newer_than_or_equal(Time.now),
+        ].each do |spec|
+          expect { repository.read(spec.result).to_a }.to match_query(/INNER\s+JOIN\s+.event_store_events./)
+        end
+      end
+
       specify "don't join events when no event filtering criteria when counting" do
         expect { repository.count(specification.stream("stream").result) }.to match_query(
           /