feat(ops-api/site-mappings): provision monitoring DB pool and readiness check

Open a separate pgx pool for the monitoring database, wire it into the
SiteDomainMappingService, and surface its health in /readyz. Point compose
at the dedicated monitoring-postgres service and align local/dev configs
with the per-instance ports. Also reformat the site_domain_mapping types
with gofmt while the files are touched.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

server/internal/ops/transport/site_domain_mapping_handler.go

@@ -11,9 +11,9 @@ import (
 
 type siteDomainMappingRequest struct {
 	RegistrableDomain string `json:"registrable_domain" binding:"required"`
-	SiteKey            string `json:"site_key"`
-	SiteName           string `json:"site_name" binding:"required"`
-	IsActive           *bool  `json:"is_active"`
+	SiteKey           string `json:"site_key"`
+	SiteName          string `json:"site_name" binding:"required"`
+	IsActive          *bool  `json:"is_active"`
 }
 
 type setSiteDomainMappingActiveRequest struct {
@@ -118,9 +118,9 @@ func (r siteDomainMappingRequest) toInput() app.SiteDomainMappingInput {
 	}
 	return app.SiteDomainMappingInput{
 		RegistrableDomain: r.RegistrableDomain,
-		SiteKey:            r.SiteKey,
-		SiteName:           r.SiteName,
-		IsActive:           active,
+		SiteKey:           r.SiteKey,
+		SiteName:          r.SiteName,
+		IsActive:          active,
 	}
 }