fix: increase VictoriaMetrics query timeout and concurrency (#145)

Grafana dashboards fail with "422: timeout exceeded during the query:
5.000 seconds" on heavy pg_stat_statements top-N queries.

Add -search.maxQueryDuration=30s (up from 5s default) and
-search.maxConcurrentRequests=4 (default with 0.75 cpus would be ~1).

https://claude.ai/code/session_01SzJxzZNQjDQphaHyaX3RU7

Author: claude

docker-compose.yml

@@ -102,6 +102,8 @@ services:
       - "-promscrape.config=/postgres_ai_configs/prometheus/prometheus.yml"
       - "-promscrape.config.strictParse=false"
       - "-promscrape.maxScrapeSize=128000000"
+      - "-search.maxQueryDuration=30s"
+      - "-search.maxConcurrentRequests=4"
     depends_on:
       config-init:
         condition: service_completed_successfully