## Summary
- The `twenty_queue_jobs_waiting_total` gauge was summing all queues
into a single value without a `queue` label, making the Grafana "Jobs
Waiting by Queue" panel show a single aggregated line instead of
per-queue breakdown.
- Uses `getMeter()` directly to call `observableResult.observe(count, {
queue: queueName })` per queue, matching the `by (queue)` grouping the
dashboard already expects.
## Test plan
- [x] Deploy and verify the Grafana "Jobs Waiting by Queue" panel
displays separate series per queue
- [x] Confirm Prometheus scrape returns
`twenty_queue_jobs_waiting_total{queue="..."}` with distinct queue
labels
Thomas Trompette
16db47fb70