Adjust VM ApplicationSet for test env + per-URL tenant routing rationale

- applicationset: ns argocd→platform, repoURL service-catalog/tenant-catalog @master
- vmagent custom-values/CUSTOM-README: per-URL 채택 근거 정정(인라인 가능하나 보안·격리 위해 per-URL)
- architecture doc: §5.1 테넌트 라우팅 결정 기록 + monitoring 배포 테스트 문서

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

manifests/applicationset/victoria-metrics/1.0.0/applicationset.yaml

@@ -2,7 +2,7 @@ apiVersion: argoproj.io/v1alpha1
 kind: ApplicationSet
 metadata:
   name: victoria-metrics
-  namespace: argocd
+  namespace: platform
 spec:
   goTemplate: true
   goTemplateOptions: ["missingkey=error"]
@@ -71,15 +71,15 @@ spec:
   template:
     metadata:
       name: "{{ .name }}"
-      namespace: argocd
+      namespace: platform
       annotations:
         argocd.argoproj.io/sync-wave: "{{ .syncWave }}"
     spec:
       project: default
       sources:
         # Source 1: 카탈로그 repo (Helm 차트)
-        - repoURL: https://gitea.example.org/dip/catalog-test
-          targetRevision: main
+        - repoURL: https://gitea.example.org/dip/service-catalog
+          targetRevision: master
           path: "{{ .chartPath }}"
           helm:
             releaseName: "{{ .name }}"
@@ -87,8 +87,8 @@ spec:
               - "{{ .baseValues }}"          # 카탈로그 차트의 정적 베이스값(custom-values)
               - $values/{{ .valuesPath }}    # Source 2의 환경 오버레이 (나중 = 우선)
         # Source 2: 값(values) repo — dip-console이 렌더한 환경별 값
-        - repoURL: https://gitea.example.org/dip/values-test
-          targetRevision: main
+        - repoURL: https://gitea.example.org/dip/tenant-catalog
+          targetRevision: master
           ref: values
       destination:
         server: https://kubernetes.default.svc