feat(horizon): add fixed-size per-queue worker pools on Coolify Cloud

Cloud production now runs one supervisor per queue (deployments, crons,
high, default, maintenance), so a busy queue cannot starve the others.
Add maintenance_queue() for slow Docker cleanups and a shared
horizon.worker_timeout config value. Self-hosted keeps the s6 supervisor.

.env.development.example

@@ -31,6 +31,15 @@ DB_PORT=5432
 
 
 
+# Coolify Cloud Horizon pools (only used when SELF_HOSTED=false and APP_ENV=production).
+# Fixed worker count per node and queue. See docs/cloud-horizon-workers.md.
+# HORIZON_DEPLOYMENTS_PROCESSES=60
+# HORIZON_CRONS_PROCESSES=60
+# HORIZON_HIGH_PROCESSES=60
+# HORIZON_DEFAULT_PROCESSES=40
+# Docker cleanups; small on purpose to bound concurrent slow remote prunes.
+# HORIZON_MAINTENANCE_PROCESSES=10
+
 # Server-Timing headers + on-screen HUD (defaults ON when APP_ENV=local).
 # Force on in any environment (including production): SERVER_TIMING_ENABLED=true
 # Force off even in local: SERVER_TIMING_ENABLED=false