REFACTOR(mas): flatten Vault paths to root level

- mas/api-keys → mas
- databases/postgresql → postgresql

mas/manifests/external-secret.yaml

@@ -13,7 +13,7 @@ spec:
   data:
   - secretKey: anthropic-api-key
     remoteRef:
-      key: mas/api-keys
+      key: mas
       property: ANTHROPIC_API_KEY
 ---
 apiVersion: external-secrets.io/v1
@@ -31,5 +31,5 @@ spec:
   data:
   - secretKey: password
     remoteRef:
-      key: databases/postgresql
+      key: postgresql
       property: PASSWORD