REFACTOR(postgresql): change vault storage

- from pg to file st...
- Remove PostgreSQL backend dependency to avoid circular reference
- Vault no longer needs vault-pg-connection secret to start
- Use Longhorn PVC for data persistence

vault/helm-values.yaml

@@ -12,7 +12,7 @@ server:
   dev:
     enabled: false
 
-  # Standalone mode with PostgreSQL backend
+  # Standalone mode with file storage
   standalone:
     enabled: true
     config: |
@@ -24,7 +24,8 @@ server:
         cluster_address = "[::]:8201"
       }
 
-      storage "postgresql" {
+      storage "file" {
+        path = "/vault/data"
       }
 
       # Optional: Enable Prometheus metrics
@@ -33,12 +34,6 @@ server:
         disable_hostname = true
       }
 
-  # Environment variables from secrets
-  extraSecretEnvironmentVars:
-    - envName: VAULT_PG_CONNECTION_URL
-      secretName: vault-pg-connection
-      secretKey: connection_url
-
   # 리소스 제한
   resources:
     requests: