chore: default local dev event store to ClickHouse in .env.example

Fresh clones left EVENT_REPOSITORY_DEFAULT_STORE unset, which falls back
to the "postgres" store. The local stack is already ClickHouse-backed
(run replication + CLICKHOUSE_URL), so dev run traces showed up empty
even though the run itself appeared. Default it to clickhouse_v2.

Author: ericallam

.env.example

@@ -17,6 +17,11 @@ NODE_ENV=development
 CLICKHOUSE_URL=http://default:password@localhost:8123
 RUN_REPLICATION_CLICKHOUSE_URL=http://default:password@localhost:8123
 RUN_REPLICATION_ENABLED=1
+# Store task run spans/traces in ClickHouse so the dashboard trace view is
+# populated in local dev. The local stack is ClickHouse-backed (see above), so
+# leaving this unset falls back to the "postgres" store and dev run traces show
+# up empty even though the run itself appears.
+EVENT_REPOSITORY_DEFAULT_STORE=clickhouse_v2
 
 # Set this to UTC because Node.js uses the system timezone
 TZ="UTC"