Log search queries (#949)

## Summary
- log search queries and result counts to metrics job

## Testing
- `bundle exec rubocop`
- `bin/codex_style_guard`
- `bundle exec bundler-audit --update`
- `bundle exec brakeman -q -w2`
-
`DATABASE_URL=postgres://postgres:postgres@localhost/community_engine_test
bundle exec rspec
spec/jobs/better_together/metrics/track_search_query_job_spec.rb`


------
https://chatgpt.com/codex/tasks/task_e_6893d6e8afdc8321885f1c9ea0fa44b0

Author: rsmithlal

app/controllers/better_together/search_controller.rb

@@ -18,6 +18,12 @@ def search # rubocop:todo Metrics/AbcSize, Metrics/MethodLength
             o['text']
           end
         end.flatten
+
+        BetterTogether::Metrics::TrackSearchQueryJob.perform_later(
+          @query,
+          search_results.length,
+          I18n.locale.to_s
+        )
       end
 
       # Use Kaminari for pagination